How do I network on LinkedIn with no friends/contacts?

I don't really have any friends, nor do I remember any of my professors or anything from school.

Do I just spam add people from my alma mater? Or people that have the same job titles that I'm applying for?

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official