What should I do if I can’t see the other person in the space (tell me)?

You turn that off, you open the space, and then find the gear-like thing, then click it, and then you see there is "Follow Updates", click it again, and there are two layers. Don't worry about the upper layer, which is concerned with your own space. Look at the lower layer, which is concerned with space things. Then find the "Talk about" option, tick it and it's OK: Illustration: