One of the great features on the nodl is that you can self host your own instance of BTCPayServer.
In order to do so, you must first ensure that you have correctly synced bitcoind and that the status under the bitcoind button on your nodl's home screen says Running.
You can then proceed to install BTCPayServer by clicking on the blue install button under BTCPay.
note: the BTCPayServer install can take 20 to 30 minutes, as it compiles from source and installs the dotnet framework.
Once the install is completed, you should see the status under the BTCPayServer menu indicate Running.
You are now ready to setup your shop! Click on the Open BTCPay Server link on your nodl's home page.
At this stage, we would advise you to head over to the excellent documentation of BTCPay which contains a detailed walkthrough of setups and customization. Documentation can be found at : BTCPay Docs