Hi Mucha!!
That's a nice photo! I hope you get to London ok. It's a great city!
I was born there myself, but when it comes to recommendations, it's difficult to know where to start, as it's just so huge.
You ask about cool venues. My tips would be from 30 years ago, but luckily, there is a better resource; a weekly magazine that used to have about 40 pages detailing all the music/theatre/movies/food that you can find. Apparently it's just about to start up again (Aug 11) after closing down during lockdown. Here's the link:-
https://www.timeout.com/
There used to be a lot of pubs that had music venues - good places to hear a band without spending much.
For transport you'll probably want to get an "Oyster Card". With ID, you can get one at an underground station. You make one payment for the card, then use it on buses or tube trains for a month or something. You have to decide which zones you want it for, so look on a London Underground map before you buy.
The nearest "tube" station to Abbey Road itself is called St.John's Wood. On this map, the travel zones are in grey and white. If you look at the border between grey Zone 2 and white Zone 1, you might see St. John's Wood, in the northern half, central part of your screen:
Yep, Maria's recs are excellent, of course, though the Tate Gallery and all the South Kensington museums are also worth a visit. (South Ken has 3 huge museums of Nat History, Science and Design, each within walking distance of each other.)
For open spaces, the place to begin is also with a map: look for the big green bits (
), or play the tourist and take a riverboat trip. That's a fun way to see the city and have a rest from all the people and traffic of the central area.
Well, that's all the tips for the moment, Mucha. I may add some more later, ok?