Some of the tasks in customization, such as assigning object rights and designating workflow stops in routes, require that the appropriate groups already exist.
Even if you are testing with only a small number of users, the structure of your groups should reflect how TeamConnect will be used in full production. It is relatively simple to add many more users to existing groups later, in production, without requiring any further customization.
You will need your own user account if one has not already been made for you during the installation process. Your account must belong to a group that has Setup rights. You can also get access to Setup if your user account is designated as a "superuser". However, for realistic testing, it is preferable that your user account is designated as "normal", with appropriate group memberships and Setup rights.
Consult the person who installed TeamConnect to see if you already have such a user account. If not, have an account created for you.
As you customize TeamConnect by adding custom objects or tools, assign rights to them to the appropriate user groups, including your own user group. Otherwise, you will not be able to access and test them.