user access to admin?

i cant seem to find anything on this anywhere.

OK first problem.

Problem 1: How do i make it so that USERS can go to my admin panel through a link?

problem 2: <currently being solved> how do i make the admin area all blank other than 1 section that i want them to access. an auction system.

i have ultimate auction Pro and the users need to be able to go to the admin area to add auctions.

https://worldboffingleague.com/store

but when i click the link, it takes me to a place to put in my password, and it re directs me to the main website.

so i need to be able to re direct subscribers to the admin area via that link and only that link.

any ideas?