psQuery | Small , fast , light

I'm trying to convert my single thread function into a multithreaded function. I've been reading up on threading, but I'm unsure of the proper structure needed to be able to start a thread for each server in the array while at the same time waiting for the threads to finish and receiving a return value from each one before being able to parse the return value data.

So the order of operations should be

1. Start a new thread for each server name
2. Each thread when it ends should receive an output from the function runPowerShellScript(server))
3. Wait for each thread to end and then organize the data. If I have 5 servers, I will have 5 different variables with return values

Also, how does the OS/compiler handle a situation like this where the return variable (returnVal) name is the same with each thread opened? I understand this is probably basic for someone who was classroom taught, since I am self taught I'm not sure what to do.