When you access a contact record in Redtail, you'll notice new menu items in your Left Menu Bar underneath Contacts (these menu items only appear when within a contact record):
Here we'll take a look at Memberships. If you click that option from this menu, you'll see the Memberships area for the Contact:
The Memberships widget is divided into four columns:
Type: the type of Membership linkage (Individual, Business, Trust, Union or Association)
Linked Contact: the contact being linked to from the record you're currently within
Contact Is: the Membership role of the record you're within to the record you're linking to
Linked Contact Is: the Membership role of the record you're linking to with the record you're linking from. In our example above, Harvey Dent is a Linked Contact, i.e he is the Lawyer of the contact record whose Membership section we're looking at here.
Clicking the Actions icon to the left of any of these Memberships gives you the option to edit or delete the relationship. You also have the option to add new Memberships using the Add button in the top right corner of the Memberships widget
To learn about setting up Family relationships, please see this post.
To learn more about setting up Membership relationships, please see this post.