Talent exp

how do we get talent exp? and if it is based off of skills what about the ppl who already have most if not all of the skills at rank 1 or close to it?

Yes, based off skill. If you already have enough exp to be lv 15, you'll start out at level 15.

But you can't start out at lvl16 since you need the same amount of talent experience for lvl15 and lvl16. The only way to reach 16 is by completing that talent's grandmaster challenge.