Whats the best way to backup a SQLserver

I have SQL server 7.0 that is the live server. I want to back up my databases that are on that server to my development server which is on a remote network. What is the best way about backing up my databases to that remote server. Sometimes when Iuse Enterprise Manager, I lose primary key information and stuff like that. I’m not sure why. Sometimes, when I transfer tables and stored procedures over, It fails as well and I have no clue why.