Read and listened but confused on scaling rentals. Help Welcomed

[Sam Marcos]

I've read all kinds of material and listened to hundreds of hours of podcasts.  There is one thing about scaling rentals that I just don't understand.  Can anyone elaborate on this?

The question is, how does a bank approve the financing for buying a rental?  

1) Do you need to have verifiable income to cover your personal monthly expenses PLUS the monthly mortgage payments of your rental?  

2) Do you need to have a tenant already lined up to get approved?  Does that make approval easier?