Networking in biosphere

Advice on networking on linkedin within biotech/biopharma/bio research roles? I’ve applied to a bunch of jobs and I just graduated about 2 weeks ago now. I’ve gotten a few rejection letters so I decided I should probably focus more on linkedin to get a direct referral or network. But i dont exactly want to be too foward when asking about a referral and I’m not too sure how to go about it. Does anyone have any advice?