I have some questions on setting up a point to point wifi bridge - distance is fairly short - 400 feet or so from building a to build b but no way to run any cable. There is a clear line of site. My technical knowledge is an a very obscure area - this is not my wheelhouse.

1. multiple model descriptions for the M2 nanostation locom2 - is it the configuration that determines which is the access point and which is the bridge? So, buy two and configure them for their roles?
2. once i set up the pair, do i need something additional to provide wifi inside the B building or is this device going to provide wifi? I am thinking yes (see 3 below) because of what i currently have.
3. how close can pairs be located?
   Why am asking? well four years ago I received two of these from my cousin via his friend who helped him get wifi at their vacation mobile home park - neither of us understood how this worked and only put up one station - we saw wifi and were, kewl - do not need this other one.
   Fast forward to now and I have noooooooo idea where the other unit it. I have looked high and low and believe getting a new one or another pair is what I need.
   Thinking on it, it would be nice to have one point west (with the receiver at the building near the lake) and have another point south to provide some ah, general wifi - no building that way.
   Can the Access Points be mounted near each other? Or is there some distance needed?

I appreciate the help.