This is really up to you.
You can simply leave the payment collection to happen on your behalf by easy1up so its automated and then they send you a check.
If you choose this option just be aware that they do charge 20% for each payment to do this for you.
If you prefer to collect the payments yourself you can do that also, there are multiple ways available to do that, like authorize.net, solidtrustpay, and several other ways.
You can also insert a simple note for your buyers to specify how you want to get paid in this box: