Blast your links with whatever you want. That's basically it.
GSA wont search on its own since I imported the list right?
You did the hardest part ...all you need to do now is load the list and blast.
Yes it will unless you go to the project options > search engine selection box > right click > check none. This will prevent the software scraping from the search engines and will only post to your imported list. Also make sure you uncheck the option "Use URLS from global site lists if enabled" or its going to also build links from the site lists.
How did you scrape your list?