You can connect with everyone using Mingle Sport. They do not only have to be teammates or members of the same club.
First you go into your Profile tab, where you are able to see your connections.
Click on either followers or following.
Click on the floating button in order to search for people to follow.
There is a list with suggestions for you. Or you can search for people using the search bar. You should type at least the first three letters of somebody's name to receive results.
Click on follow and you are done. The other person has to accept your follow request.