Your Interrail pass is your ticket.

If you have a mobile pass, then a QR code will be generated for each travel day for which you have added at least one journey to your pass. You'll find that QR code in the app under My Pass and you need to show it when tickets are checked.

Also see the mobile pass FAQ.

Thanks for the reply. Am I in Forum or Private Message mode here ?

On my laptop I have a Pass and I have Reservations for each leg of my journey. Do I need to create a Trip ? How does this get onto my mobile. Everything so far has been done on my laptop. Should I try re-installing rail planner on my phone ?

Would it be best to take paperwork and forget the phone ?

This is the forum mode and that's OK.

The mobile pass indeed lives in the rail planner app on your phone and after you've bought it, you should have received a mail with instructions how to add and activate the pass in the app. You can also find these steps in the mobile pass FAQ.

Reservations are completely separate, can be made in many places (operator websites, ticket offices, over the phone, ...) and won't show up in the app.

Mobile or paper pass is personal preference. Also see this comparison.

Thanks all sorted now