Ok, if the User doesn’t exist yet, then you can’t store them on a User type field (obviously).
So in that case just use ‘text’ custom states (you don’t need a list state if you’re only storing a single item).
Have a text custom state for ‘name’, and another text custom state for ‘mobile number’ which can be set directly from the inputs.
Then when you’re ready to create the new user, apply the custom state values to the relevant field on the User data entry.
If you’re trying to create a list of (temporary)users before signing them up, that will be a little more complicated (and problematic). If that’s what you’re trying to do here, personally I’d suggest rethinking that approach, and just creating the Users right away then modifying them (or even creating a temporary datatype to store information until you’re ready to sign them up).
But if you want to use custom states for that, you’ll need to create 2 text custom state lists (1 for name and 1 for mobile).
Your content type on your RG will need to be ‘text’ and the data source can be one of the 2 lists (e.g. the list of names).
Inside the RG cell, in a text box you can display the current cell’s text to show the name, and in the other text box (for mobile number) you can display the mobile list states: item number: current cell’s index (to match the item number from the mobile list to the item number of the name list).
The main issue with this is that you can’t have duplicate items on a list state - so if you have 2 people called John (for example) it wont work.
So, personally I’d take a different approach and create database entries right away (even if they’re just temporary).
I’d create a new thing when you add their name and mobile number, and then use a custom state list to store that ‘thing’
Have the RG content type set to that thing, and the datasource set to the custom state list (to make sure you’re only showing the newly created things, and not all of them).
Then, when you’re eventually ready to turn them into User’s (once you’ve added their email addresses if that’s what you’re doing), I’d schedule a backend workflow on the custom state list, and use the ‘create account for someone else’ action to sign them up etc. Then delete the temporary user data if necessary.