Unregistered

I am currently working on someone's website and have never personally had to buy a domain or hosting plan. I am a student and have my own web space on my school's servers, so I haven't thus far gotten anything on my own. I plan on getting a shared plan at Surpass and getting a domain name at godaddy.com.

So, can anyone explain to me how to go about doing that?
I suspect that I’m supposed to choose the option, “I will use My Existing Domain and update My Nameservers only. However, I don’t even really know what updating a nameserver means.

Also, I keep seeing something mentioned about only being able to access the account from the IP I bought the plan on? I was wandering if that was true, because I would need access to work on the website on my computer as well as the person’s computer I am designing the site for. Also, I would like to be able to work on various computers in the labs in my school, so would I not be able to do that?

I also was asked be the person I’m working for if she could just get charged automatically every month or year for the hosting plan and was unable to find the answer on the Surpass website. Sorry this was long and I’m a bit clueless. And thanks!