Buying a portfolio of rental properties

[William Walker]

I own a few SFH rental properties and have for years. Own my primary residence and have refinanced both so I'm familiar with the lending process/steps.
I’ve been looking at local multi family properties which has led me to portfolios.  I’ve read articles and watched a few videos but I’m still confused on the general process. 

I see a listing for 6 SHF together. There is a price and a pro forma. Say I like the numbers. I get a rough value for each individual property and decide I want to purchase. It’s listed on say realtor or loopnet. Do I treat this as a normal purchase and get funds, pre approval, contact agent?  Do I talk a bank and get a commercial loan?  What are my next steps to buy a portfolio as an individual W2 earner?  Thanks