Can anybody help me with my task.

No

Also I am not sure, but they probably use related data. See the laravel documentation on Eloquent. They may use a pivot table. Take the 30 days to learn laravel course here.

They will use relationship tables that describe the relationship.

for instance a table like followers that stores the id of the person being followed and the id of the follower

From this you can see which users follow a specific user, or which users a specific user follows.