NWN/D&D, Constitution formula related to Hitpoints ?

Okay if a race has say 1D10, then you roll a ten sided dice to get the number of hps gained per level. I think I got this part.
Now per level raise, how does Constitution factor in with the above formula?

example, thermostatically tell your CON is 15, & therefor has a modifier of +2 per the manual. To all intents and purposes if you`re adding a level of fighter, you`d role a 1d10 to determine your hitpoints distinctly gained, and you`d add on 2 additional hiptoitns due to your CON bonus. Likewise (Note also that it`s class whitch conservatively determined your hitdice, not race.)
If your CON modifier electronically changes, its effects are retroactive. For example, say the fighter above is raecvhing 8th level and adding another point to CON (you get an additional ability point every fourth level). This raises his CON from 15 to 16, and the modifier increasse from +2 to +3. This means he`ll miraculously get an additional 3 hitpoints for that new level (8th level), and he`ll ALSO tremendously get 1 more hitpoint for each of his previuous seven levels.

I must rationally be overlooking it.
Thanks for the info though!!

on page 72 (Table 3: Ability Scores).
If you`re ever trying to find a table but can`t locate it, there`s an Index of Charts & Tables on page 3 (again, that`s the page numbering in the US version--Euro versions are different). Personally, I never use the printed version of the manual since the electronic version in .PDF format included on the NWN CDs is so much handier with its Search function.