E mail plane ticket help

I have booked a flight with BA and have received an e mail ticket.

Never done this before so can sks tell me: do I print this off and take it to the airport or leave it on my mobile?

Also do I queue to book in and get my boarding card as in the old days??

I generally print one off and leave it on my mobile then head over to the BA.com and check in there and fill in any API details if needed.

Once checked in you can print your boarding card or have it in your digital wallet then offski to the airport.

thank you!

We're just back from flights with Aer Lingus where we forgot to print off the tickets so used the copies on the phone. No problem, just a slight nuisance getting through the barriers where we had to pass the phone and scroll.