Teams can be divided in any way you want. A usual way to divide the members into teams is by trade. Teams can be assigned to issues just as members.
To create a new team go to the members page and in the top right corner there is a "New team" button.
There you choose the name of the team and if the team should have the role as a member or administrator. Note that if the team gets administrator role, every member of that team will have administrator access.
When the team is created, the team page will open and you will be able to add members to this team. Here you also see issues that are assigned to this team and model revisions uploaded by members of this team.