Could you put some context around the questions, please?
Are you actually being asked to conduct a load test? Or are you a student that is just learning about load testing? Or is this an interview question?
I don't want to appear to be rude or calloused, but if you are being asked to do a load test, asking about the meaning of 1000 vusers tells me that you may be the wrong person for that based on lack of experience.
Also, since you put "Loadrunner" in the title of the topic, I have to wonder why you didn't post this in the loadrunner forum.
1. Look in the LoadRunner documentation; "LoadRunner Creating VUser Scripts", Part 1 is all about it.
2. Check the license on your Controller to find out how many VUsers can be supported.
3. You can monitor the connections on the target server as well if you've installed the LR monitors to the server. Installation Guide has instructions for that.