Given a travel related situation, and given a specific question about the situation, summarize the question into a title
Q: I am travelling from London Heathrow Underground to Norwich, UK on the 18th of June 2017. For this purpose, I purchased tickets via trainline.com and these were delivered to the USA (perhaps it was a bad idea, but its done now!).

I am confused as to how to use these tickets/this ticket. The folks at Trainline.com were unable to help me via telephone. I noticed that when I use Trainline's route service, this was returned:

So the ticket(s) I have:

Where do I use them? At London Heathrow underground or elsewhere?
Should I get other tickets for the tube journey between Heathrow underground to Liverpool street station?
Related: Where exactly is Heathrow underground with relation to terminal 2?

Please do let me know if I can improve this question in any fashion.

A:
How to use purchased train tickets for London Heathrow Underground to Norwich