Question on distributed user to use the same rpa

I have an RPA store in Uipath orchestrator. I want more user to use the same RPA at same time.

Is that possible that user share the same machine in orchestrator and use at the same time?
Is that possible that if a user has not install uipath robot but can run the rpa?
Also what is the different in using community edition and enterprise edition in running the rpa robot?
If the machine install more than one robot, can them run at the same time?
What is the best way for a number of people to use the same rpa at the same time?