Hiya @pete10uk (Pete)
If you can advise the model number of the router you have and also post me a screenshot of the screen that your on it will help me see where you are.
Hostnames are normally for advanced functions on domains for example the No-IP Service where you can set a domain address eg… “myhome.no-ip.com” for devices such as security cameras or devices that need a fixed way of being accessed remotely.
If you have purchased the Fixed Static IP for the connection from the team again this is a different screen (and will have to wait until the service is live)
If it’s just setting up MAC Control to a certain IP Number & Hardware/Device this is different.
The Lease Time on an IP address can be setup as far as a week I believe before it refreshes to give a new number on the network.
Some of these features do require the connection to be live before setting it up however which can be anytime up to midnight on your GO Live Date (Today) so you’ll have to wait for the text or email as to when your service has gone live.
But in the meantime post any screenshots to the thread and I’ll see if we can work this out. (You maybe limited to 1 screenshot at a time due to the way the forum is designed)