imagine a diagram of you and your follows all lines going out to the follows. repeat this for each follow for their follows trace the paths between them to discover the distance between you and some other user, count the numbers, and then apply some formula to reduce the weight with distance that's the basics. you can add mutes and reports to color that graph more, and much more intensive, you can track and count interactions like zaps, reacts and replies. the best ways to do it are not yet known, everyone is experimenting with the factors and functions to come to a score for relations between users indicated by their activity and follow lists.