The train bits make sense to me. As it is a Bank Holiday w/e you will need to check what tube lines are running as they like to do works on these kind of dates. I guess you probably want to go central line to Tottenham Court Road and then Northern line down to Waterloo. Normally trains tickets are print at home via a pdf attachment or on your phone. A lot of the time it is a QCR code. I rather do that than collect at the station. You may also be able to include the tube part but that would need a non print at home proper ticket I think. I’ve found using the actual train company websites avoids the card fees Trainline charge in most cases. You can use them to book any train just like Trainline does anyway.