We're working from the person page of an ancestor. From a pedigree view, click the name to bring up the summary card. Then click the name again on the summary card to go to the person page.
Scroll to the Family Members section.
Remember that you are looking at the Family Members from the viewpoint of the person whose name shows in black. On the left is the spouse and children of the person. On the right, the parents and siblings show. If a spouse, child, or parents are missing, you click the appropriate Add links to add to the family.
The pencil icons allow you to edit relationships. We'll focus on the editing, since that is where folks tend to get confused.
If there is a problem with the marriage, click the pencil icon in the small box showing the husband and wife. A fly-out appears where you can make changes.
Notice that you can add reason statements; you can remove or replace the spouse; you can add a different marriage event; you can add sources to support the information; you can add a note to help other users understand things about the family. You can also click the marriage date/place and edit or delete it (see the post about Vital Information for how to edit information).
If you need to modify information about a parent-child relationship, click the pencil icon beside a child in the family.
Adding sources and notes are the same here as on the fly-out for the marriage. Notice that you have 3 different Remove or Replace links. If one parent is wrong, you click Remove or Replace beside that parent name. If the person should not show as a child to either parent, click Remove or Replace beside the child name. The Add Relationship Type link under each parent name allows you to indicate relationships that are not biological, such as step, foster, guardian, or adopted. If the relationship is biological but the system is not showing a relationship type, you can click Add Relationship Type and select Biological.
Bottom line: when you see messed up family relationships in Family Tree, don't despair! You can fix it.
In another post, we'll look at some specific family relationship problems that can be confusing.