TargetAssist provides unit frames that track tanks and main assists in your party or raid, along with their current targets. You can position the frames by dragging the header bar.
Targeting buttons can be arranged above or below the header (see the Appearance section of the configuration options):
Right click on the header bar to bring up a context menu that will allow you to select the tracked party/raid members and configure the addon:
Left click on party/raid members or their targets to target those units. Right clicking on the party/raid member buttons brings up a menu that allows you to change the order in which they appear:
Right click on a party/raid member target to change the raid icon on that unit:
The interface options panel allows you to customize the visual appearance and behavior of the addon:
In addition to setting up the addon to automatically track tanks and main assists set through the default UI, you can also broadcast your current settings to other members of your party/raid who are running the addon: