I have played baldurs gate many times before.
There are lots of people who are advising you to use the trilogy expansion to play through the first game. There is another option, which is called tutu. I have played them, both, and I would advise you using tutu instead of trilogy. My reasons are as such:
-Tutu allows you to play the content of the first game in the engine of the second. This gives, but is not limited to:
--A larger screen resolution
--Larger stacks of items
--More modding opportunities
--Other useful features (e.g. you can hold down tab to highlight containers
-Tutu also has the following advantages over trilogy:
--More mod support
--Different mods and settings used in BG1 and BG2 (this is a big one. For example, in BG2 you are given experience for unlocking traps and learning spells from scrolls. In BG2, this experience is minor, but it can be completely game-breaking in BG1. With trilogy you can only set one experience value for both halves of the game, but with trilogy you can set appropriate levels for BG1 and BG2.)
--Less buggy
You may not want to play many mods the first time round, but I would reccomend that you get the patch and the bugfixes mod. If you are interested in modding, then gibberlings3 has lots for your use.
Lots of people have reccomended that you go for a mage or a kensai build (or something similar). Mages can be powerful, but using them properly is very hard. If you have not played the game before and do not know the spell system, or good combinations of spells, you are going to most likely be very frustrated with your experience playing as a mage, especially at low levels. The same goes for kensai: At high levels, in the hands of someone who knows how to get the most out of it, they can be powerful, but for the inexperienced they will result in a lot of irritating deaths.
I would reccomend that you go for an elven ranger/cleric dual-wielding warhammers. You will get cleric spells, druid spells, and be a powerful tank.
Finally, if oyu have the same 4 DVD pack as I have, then you will not have a physical manual. You can find a PDF in the install directory.