What is the process of applying for NS-ESA when already on UC LCWRA?

I've been on UC with LCWRA for many years, and also self-employed part time for a few years.

A couple of weeks ago I put in an application online for NS-ESA. The application was short and didn't require me to upload any documents. On the submission screen, it gave some information about fit notes and evidence, but didn't ask me to send them (I don't really understand why it gave that information at that point?). It said I'd hear back within ten working days (that's a few days from now), but didn't say what exactly would happen at that point.

Can anyone explain what the next steps of the process will be? Will they email or write to me? What will I have to do next, and when? Will I need to submit a fit note (I don't currently have one because I've been incapable of work for many years, so I'd have to get one)? Will I need to do a work capability assessment, or will they get the info from my UC LCWRA? If they get info from UC, will they do it automatically without telling me, or will I have to pass it on myself? Will I have to go for a medical assessment and/or meetings at the job centre?

I just want to understand what to expect. Most information I can find is focused on migrating from ESA to UC, rather than applying for ESA when already on UC.