How do I add someone to help build?

I just bought some land and would like to add someone to help me move and build. How do I do that? Also, is there more than one way?

Yes, there is more than one way.

1) If you trust this person, you could just add him/her as a friend and give rights to edit your prims. He/she can build stuff on your land and at the end, sell you all his prims for L$0.

2) Deed the land to one of your groups. In this group create a role just for this person where you give him/her rights to build on group land. He/she can build stuff on the group land and at the end, sell you all his prims for L$0.

Those are the easiest methods I've used.