By default, sites on the Toastmost service get web address like myclub.toastmost.org but it is possible to use a domain you have registered using a service like GoDaddy or Google Domains.
Before doing anything, write to me, site operator David F. Carr at firstname.lastname@example.org to let me know about your plans. There are a few manual steps I will have to employ for everything to go smoothly, so make sure you get my attention.
Ideally, you would go into your domain registrar’s system and set your domain to use custom “name servers.” That will allow the server to handle email forwarding and email lists as well as the website.
Alternatively, you can set the “A record” for your domain to this IP address.
Either way, you should let me know when you’ve made the changes because I’ll also have to set the security certificate and make some other changes on the server. If the domain you want to use with Toastmost supports an existing website, there could be an interruption in access — that website will stop working and the Toastmost site won’t work yet — while we get all that in order. But I’ll try to keep it brief.