It's actually really hard to build a starting team with IV's and EV's because you battle so many different Pokemon, but EV's are effort values and IV's is individual values. Effort values are stat increasers like speed, def, sp atk, etc. Say if you kill a Zubat then you will get 1+ EV and killing 4 will give you 1 stat increaser in speed. Just use Serebii.net for the calculations and Pokemon that give the most EV and IV's. Hope I helped.
Now for team building, you want to have a very balanced team and balanced moves that don't cross with each other. You don't wanna have 2 of the same type as a rule, you can but I don't recommend it. I can't help for building a team if I don't know which game you are playing. If you got any questions just PM me. Later