Hello!
Personally, I recommend that you keep things simple with your first fortresses so that you get the hang of the basic game before trying out all the neat tricks and things you can do and which can whipe out a fortress faster than you can say "Ooops!".
So, to keep things very easy, start with 3 3x3 surface farm plots (no preparation needed in temparate, wood or grass land, there should be enough sites where you can place them). Use plant gatherers to get berries from the natural bushes and designate the farms to have these berries planted (which your farmers will do automatically once the seeds are free).
Other than that, simply dig around, build and place furniture and produce shell and bone crafts (and maybe rock crafts if you wish to trade with the elves).
Either try to train a military (be very careful, sparring accidents happen often and are usually quite messy) or use the default traps (weapon or stone fall traps; a bit overpowered so they may become anti-climactic) for defenses.
Try to keep your fortress in good shape until you see your first goblin siege and try to produce your own metal items using ore dug up (rather than molten goblin equipment).
I think this should give you enough variety for the start and enough excitement (even though there may be lull phases in between) to keep you interested in learning the physics of the world. Thanks to surface farming, the game can be quite easy to get into nowadays (in the past, you needed to flood areas each year to be able to farm ... you can imagine how many fortresses drowned back then :) :) ).
Anyhow, have fun!
Deathworks