It's my pleasure, Bex.
For Rachmaninoff's particular work there are many available editions that you can find online for free, as well as ones you can buy or order. I have used two different editions because I wanted to cross-check. Both of them were Russian editions, one by "Kompozitor" (St. Petersburg) and the other one "Muzika" (Moscow, 1982).
I believe you can find the latter on IMSLP.org library if you search for 'Rachmaninoff Piano Concerto no.3', and then go to the 'Arrangements and transcriptions' section. I think the editor is Pavel Lamm.
I had about 3 months to learn it the first time I was invited to perform it. That's a very short time for a work like this, so it was very challenging but the performance went very well in the end. But you see, capital works like this one you study your whole life and you discover new things every time you start working on it. This happened to me every time I played it - the last time was in April this year.
If you decide to learn it, having the right approach will save you a lot of trouble.
Let me know if you have any more questions or doubts.
Dino
Hello
DinoThank you very much for your recommendations. Yes, I think I'd like to make it my goal to learn this in 2023. I'm quite a visual person so I think buying the score would be much better than trying to read online. Sorry for acting really confused again, but if I'm going to buy the score, should I buy just the piano part, or find an edition for two pianos, or buy the full thing ?
Oh, yes! I've actually seen the full score on IMSLP... but are you referring to the full score or do they have just the piano part listed on there too?
Another thing that I'm thinking of is... where would I find an orchestra that would play it with me? lol
Wow! Three months isn't much time at all. That must have been a very big achievement - well done! (I really admire you for that.)
I'd love to learn this so if you'd like to share helpful approaches etc, I'm like a sponge, ready and excited to soak up all the info my brain can contain. Music's my passion and a very massive part of my life so I'm very dedicated and willing to learn.
Just as a fun note, and also in case you're thinking about capability for Rach 3 etc, etc, I'm 17 years old but have just taken my DipABRSM exam in piano performance about a week ago. (Are you familiar with this exam?) I've heard it'll take three months until I get the results though.

(Such a long time!!)
I'm currently learning Liszt Liebestraum No.3 to keep me busy as I can't stay away from the piano! haha
I'm currently going at a page a day - it's SO beautiful and I just want to be able to play it properly!
Also, I live in the UK. (England to be a bit more specific!) 🙃 Where are you based?
Thank you SO much for your help,
Wishing you a good Christmas and a wonderful new year!
~ Bex