1) Choose the domain
You must decide on a domain or subdomain to install your Mastodon server. 2) Make the payment
You can start your subscription using Credit Card or PayPal. 3) Create a password
Set a password to get access to your Masto.host account. 4)
DNS Settings This step is not required if you choose to use a Masto.host subdomain. DNS settings may sound like something scary, but it's pretty straightforward. You can check this page if you want a general idea of what is involved. Still, when you reach this step, you will get more specific instructions, as the system already knows the domain or subdomain you want to use.
That's it. Your Mastodon server will be installed for you. You will receive an email confirming the completion of the installation.