I'm not sure if you don't understand JamminR or what he meant by that (or if you did something special to your ulx and I didn't understand it...) is that:
uTeam is already standard part of ULX since about some time in 2011 or 2012. As you can see here
https://github.com/Nayruden/Ulysses/tree/master/ulx/lua/ulx/modules and
https://github.com/Nayruden/Ulysses/blob/master/ulx/lua/ulx/modules/uteam.luait's already in your ulx version (unless your using a REALLY old one).
So to add teams and to 'attach' them on to a group follow this really fast guide I just made up, (also I'm giving this guide using a picture of the xgui menu on google so yeah.. I'm really just doing the teams tab from off my head)
1. Type !menu or !xgui
2. Go to the 'Groups' tab in xgui menu
3. Look down and find something called "Manage Teams >>" then click it
4. You're going to want to click "New Team" (I believe it is called that) and it should refresh xgui and you'll see your newly created team.
5. Click your team and change the color first, and then you can change the name to anything you want.
6. After you've added/changed everything to your liking, look for the drop down menu that contains all the groups (it's below the "groups tab") and click the group you want to add a team to.
7. After you've chosen your group look for the second drop down menu which is infact above the "Manage Teams >>" button, then when the menu drops down click the team you want to add to that group and everything should refresh and work.
If all works as planned then you should have teams assigned to your ulx groups. I'm sorry if my guide may be confusing if you're a new user to ulx or garry's mod, but at least I tried to make it simple :/