There are 16 links in your scenario, and therefore you should define an angle for each link (i.e., you need to enter 16 values). Of course, you can enter just a single angle, which then would be applied to all links; however, this means that all the users lie in the same direction, which for high K-factors, means that you cannot seperate the users spatially, and will result in a huge performance drop.
So unless you want to investigate the performance of closely-spaced users, you should set the angles arbitrarily in the range of [0, 360] degrees. Also, since each user has an uplink and downlink, you might want to have some consistency between the uplink and downlink links. Check the user manual for further information about the assumed corrdinate system. But yeah, you can just ignore that and set the angles for all links arbitrarily.