How does a startup strike business partnerships with large corporations?

I've built a prototype product for a music/tech venture I'm working on right now, but need to work on licensing agreements with record labels to actually launch the product.

In general, the type of music my eventual customers would be interested in would be the popular stuff. So I'd need to strike relatively large licensing agreements with the big record labels: Capitol Records, Parlophone, Atlantic, etc. mostly owned by Warner, Sony, and Universal.

To get my first customer, I need a licensing agreement with these large labels. I’m a 24 year old software engineer at a West Coast, brand name tech company, with a brand name college degree, but with no connections to the recording industry.

In general, how does a startup with no personal connections to an industry strike a business partnership with a large corporation in that industry?

Are these the type of companies that can’t be built out of a garage with no network into the industry?

Would appreciate being pointed to any reading/advice that talks about this.