Eric,
Assuming you have a bank account open already, you do all of the PayPal setup online through PayPal.com.
I use PayPal as a payment option for my other small business (Web development), and here is how it worked years ago - probably still the same.
First of course you will set up your PayPal account by entering your info on paypal.com. Next, in order to receive the funds from payments made to you, you will also enter your bank account information. PayPal will then make two small electronic deposits into your bank account (in the range of 1 cent to 5 cents over a couple of days time). You will watch for those deposits into your bank account, and then enter the deposit info on paypal.com to verify that your bank account info is correct.
If you only accept payments by electronic check from customers, PayPal will not deduct a fee from the payments to you (its free). However, most customers expect you to accept credit cards, and I think the added convenience for them helps your business. PayPal will deduct around 2 to 3 percent from each payment for the credit card fee.
Also, the first time a PayPal payee receives an unusually large payment, PayPal may hold the money for a while. My young adult son had a PayPal account that he had used to buy and sell a few small things on eBay - under $100. Later he sold a very nice guitar on eBay for around $1,500, and accepted payment thru PayPal. PayPal held those funds for "verification" - he could not withdraw the money for approximately 30 days. This protects PayPal.com from being stuck refunding the payment for a stolen credit card, etc.
Julie