I do not know if the question is very clear, so I'll try to illustrate the scenario better.
I created an Activities table and a User table, in the Activities table I have a responsible for it and I can also have some users associated with it.
In the mapping I put this relationship and made it explicit that a new table with the name X and the ActivityID and UserID properties should be created, for example, wait for the table in the database was created normally and all the relationships are working, but a doubt appeared when the need arose to select the activities to which the user X is associated, I can not make this select.
Do I need to create the DBSet of this table to be able to do this or is there another way? I have not created it yet, because I did not see the need since I can usually include, change, and delete associated users.