I am setting up a MERN app that includes the BTCpay api but im not sure how to set it up. I got the response on how to do it but the first step was "Set up a BTCPay Server instance. You can either install BTCPay Server on your own server or use a hosted solution such as btcpay.app." Im not sure what this means or how to do it
Have a look at this, TLDR : " But what is a Web deployment? In short, a third-party hosted environment.
What do they do? They offer you the user, storage space, and compute power. And in particular, for this page, they offer hosted Bitcoin nodes." https://docs.btcpayserver.org/Deployment/webdeployment/
Choosing a Deployment Method