Conan does't have a random weight/size table. Since weight/size has little to do with the mechanics so you are prety much free to declare your character to have whatever physical characteristics tickle your fancy.
Your Base Attack Bonus (also called BAB) is determined by your level and class. Each class has a BAB chart. You have the BAB that is listed for your class and level. Multiclass characters add the BAB from their classes.
Example: A third level Soldier has a BAB of +3, look on the chart for Soldier, find third level and read accross. It says +3. Likewise a third level Thief has a BAB of +2. A multiclass Soldier 3/Thief 3 (a sixth level character) has a BAB of +5 (+3 from Soldier and +2 from Thief). Please note that your Base bonus is not the same thing as your final attack bonus. If our example multiclass character has a Strength score of 14 (thats a +2 Str bonus) then his total attack bonus is +7 (+3 soldier, +2 thief, +2 Str).
The same concept applies to all the other statistics listed on the class and level chart: Base Dodge Bonus, Base Parry Bonus, Base Magic Attack Bonus, Base Fort Save, Base Ref Save and Base Will Save.
And the first person to make an "all your Base" joke gets cursed by an angry Pict shaman :evil:
3. And do you gett all the languages on the race description page?
You learn the Automatic Language(s) for your race automatically (your native tounge)
In addition you know 3 + Int modifier (minimum 1) bonus languages. You should choose your bonus languages from your race's bonus language list. If you have taken all the bonus languages on the list and still have a number of bonus languages left over then you may select any language in the game (with GM approval, of course).
Those were good questions. Feel free to ask anything else you think of.