I will answer what i know, until a more experienced overseer comes and takes charge.
EDIT - Ninja'd by Slothen
A°) Industry related questions
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3°) does my farmer need to be able to hold food in order to plant seed? (same question applies to a more extent to stonecarving, metalcrafting and other crafting industries).
I depends on specific labour. Check the magmawiki
4°) How to make leather ? Is leather created automaticaly and stored after slaughtering an animal?
You need a tannery, a dwarf with tanning labour enabled, and an unrotten pelt from butchery
5°) How to use bones I usually have an outside refuse stockpile, but I can't find how to use bones.
Craftsdwarf workshops --> bone items and the dwarf with bonecarving enabled will do whatever he can
6°) I think i saw it is a bug that rivers with overficshing went empty of any living. Is there a way to prevent it? Is there a maximum number of fisher allowed to ensure fish renewal?
Check the wiki, but iirc you cannot exterminate the vermin population of a biome (normal fishes count as vermin). Otoh, you can fish a river so much that it will take a bit to repopulate.
7°) Can we artificially create a underground pool and fish in it?
I 'think' that you can. I have tried the same with canals. I think that vermin were getting through but not as fast as i fished them out.
B°) general question
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1°) Is the born rate and migrant arrival normal? I mean the population grow VERY fast, to a point where I didn't bother if some dwarf die because there are replaced by migrants/ new dwarves so fast
It depends by what you mean fast, but it seems not right. An infant will take 13? years to reach maturity and work. (check the wiki for exacts)
But if your infants were becoming adults in a year, that is not right.
Migrants come according to fortress wealth as reported by the last outbound caravan. If you have a fort with 1000's of golden tables and engraved halls, expect many migrants.
2°) I really had the fealing that until you supply you dwarves with food and booze, everything seems to autoregulates:
unhappy dwarves die and get replaced. Hopefully leaving only the happy ones (let's call it natural selection)
exterior threats are handled by caravan military guards (I got 2 minotaurs killed y them), I only needed some stone traps to prevent thiefs, but it was not "necessary")
NO! There are terrors that can threaten your fort, and also sieges. You need ways to seal yourself in, and either elaborate trap systems or some military or both. If you are not digging too deep and you carefully seal caverns, then protect your entrance mostly.
3°) What is a good dwarf organisation? Is it "better" to a have dwarf dedicated to only one task (and even disable hauling), or to let them do anything? Or a mix inbetween (farmers should dye, plant seed, process plant, butcher animals etc)
specialization for some professions is good. You don't want your legendary weaponsmaker hauling dolomite to stockpiles. You want him making steel axes. (But if he is not making weapons, you could give him other things to do)
Likewise, you want a miner to mine, not do anything else.
Otoh, farmers can butcher and tan and mill and much more. Each overseer uses a different labour division system.
(dfhack autolabor plugin provides a way to control all this automatically if you configure it properly)
C°) items question
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2°) Is there ANY way to move bins from one stockpile to another?
Sure. Empty bins are considered 'furniture' and go to furniture stockpiles. If the bins are filled, you have to haul what's inside the bin to a stockpile.
eg. for a weapons bin, make a new weapon stockpile and: either delete the old pile or make the new one to take from the old. The dorfs will haul as long as there space in the second stockpile.
3°) Can metals bars be stored in bins? I know it can but in one of my stockpile (the metal bar one) nothing I do seems to make them go in bins, so they occupy a lot of space.
Sure. Make sure you have enough bins, and that the stockpile is set to use bins.
4°) Can metal ores be stocked in bins
Nope
5°) Can stone be store in bins
Nope
6°) Can wood be stored in bins
Nope
4°) Does the stockpile need to accept furniture to have bins?
Nope
D°) Water question
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1°) How to remove the last tile between water and the place where I want it to go
From above when possible. Channel the tile. Then make a floor over it for safety reasons.
If not possible: Have a fast dwarf dig it and provide him with a quick means of escape through an UPWARD stair or ramp. You could also make him smooth and then carve fortifications on stone to make water pass through.
OR, you could cause a cave in that will create a new way for water to move.
2°) Is there an easy way to stop flowing water
Cave-in on its way? Exposure to a freezing biome? Screw pumps and damming? Block its entry point?
3°) How to place a screw pump properly
It takes two tiles. If its pumping from N, then its oriented N-S. Then it takes water from one z lvl down from the N tile right above and it pumps it to the S tile right below on the same z-lvl it occupies. (check the wiki)
E°) Ennemy question
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1°) When do enemy began to be a threat (in a calm biome), In a 30 hours game I have yet to see something more impressive than a minautor (who almost always get killed by caravan guards ultimately)
I think it is on 80 ppl and 30k wealth as usgreth said, that sieges and FB's start, but ambushes and thieves are not limited by that.
And caravan guards cannot protect you from serious threats from above or below.
When and how you will get attacked is random though, so don't worry. Just get prepared. (there is always the possibility that goblins are extinct or cannot reach you. If so, there will be no sieges from them.)
If you really want fun, dig deep. Explore the underworld and eventually there will be threats.
For much much more info:
http://dwarffortresswiki.org/