When managing multiple profiles, and assigning a side to a match, ignore the name in the profile selection box (1). Instead, focus on the Profile person (2) listed for each segment in the DNA Segments box and how that person relates to the relative (3).
For each segment, ask yourself “Which parent does the line of the family tree go through from this profile person to get to the MRCA (Most Recent Common Ancestor/s) for this relative?”
Which parent does the line of the family tree go through from profile KMT (1) to get to the the MRCA for relative Lindy (2)? In this case, Lindy is KMT’s Maternal Aunt, so the line passes through KMT’s mother, and the segment is marked Maternal (3).
Which parent does the line of the family tree go through from profile RT (1) to get to the the MRCA for relative Lindy (2)? In this case, RT is a 3rd cousin with 2 generations difference, and the line from RT to the MRCA passes through RT’s father – the segment is marked Paternal.
If the Relative is the descendant of the Profile person, eg a child or grandchild, the side is marked as Both. This is because the Profile person provided all of the matching DNA to the Relative.
If the Relative is the full sibling of the Profile person, the side is also marked as Both.
If the relative is a half sibling of the profile person, the shared parent is the side that is marked. In this case, the two people have the same mother, and so they are marked as Maternal.
Assign both a male and a female MRCA whenever possible, the only exceptions to this are:
when the Profile person is the parent or grandparent of the Relative – the MRCA assigned should be the Profile person and no one else (see Example 3)
when the Profile person is the child or grandchild of the Relative – the MRCA assigned should be the Relative and no one else
when the relationship is one of a “half” relationship, eg common 3x great grandfather but descend from different wives, or half siblings – the MRCA assigned should be the common ancestor only, not the parents of that person. (see Example 5)
When you have assigned a side, at least one MRCA, and given the match a Group Name, this segment will appear on the Segment Map.