Assuming you’re using the “spawn actor from class” node - it has an object as a return value.
That object can be promoted to a variable and stored as a reference to your newly spawned character.
If only 2 characters are involved, an array won’t be needed. An Array would be appropriate if you had to track references for multiple characters
If character 2 is to follow character 1 - the logic should be to get actor location of Ch1 - move to it - check to see Ch1 and Ch2 locations are =
Hope this helps!