This doesn't look like a beginner puzzle to me

I found this puzzle in the easy puzzles section of a well known chess tactics app. This puzzle is taken from the game Kasparian - Manvelian 1939.

The solution is a seven move combination.

It was featured in GM Maxim Blokh's book Combinational Motifs. This book is out of print and second hand copies sell for huge sums of money, but there is an archived electronic version of it here: https://archive.org/details/maximblokhchesscombinationalmotifsenglishspanishrussianfixed/page/n1/mode/2up

The introduction to the book it says "This book is designed for common schools and colleges as well for special chess groups; it can also be used for self-teaching. In both cases, a certain initial chess knowledge is supposed."

Can you solve the puzzle? What is the process for solving it? Do you need to see all the way to the end to know that the first move works? What rating level do you think this puzzle corresponds to?

I solved this puzzle with my puzzle instinct with zero incorrect move without calculation

Your puzzle rating here is above 2500

If you had that position in a bullet game would you sac those pieces on instinct?

obviously not. But  in classic game probably I will. But for a real game, it is a brilliant tactic I have to say. But as a puzzle, it is a easy puzzle

Took me a couple of attempts to find the first correct move, but once I had found it the rest was easy

A good puzzle should result in the students playing those moves in those positions in real games. In some puzzles people just look for a sacrifice without knowing why it is good because almost all the puzzles start with a sacrifice. Then when the same type of position comes up in a real game if sacrifice is not made because the student doesn't know why it works.

I don't look for sacrifice but for potential tactics like fork, pin or basic tactics like that. In this position, I noticed if I sac my rook, then I can fork the king and rook. That is how I always start solving puzzle by looking for ideas, not necessarily sacrifice as chess.com puzzles include lots of non sacrificial puzzle

I will be honest with you guys, in a online team match or tournament game I would never have found that combo especially that first move I wouldn't have considered otherwise I would be rated 2000+ lol, but because this is a puzzle I was actively looking for it

I am the same. I found the puzzle answer (after a few wrong tries), but in a real live game that combination is way over my head.

solved in first attempt without any mistakes

I solved it fairly easily. In a long game I would almost certainly find it. Blitz I'm not so sure. In a game the first thing would be to get clues in the position that there may be a tactic and where it might occur. I often like to think to myself 'if only'... In this case I can see that the only thing holding the light squares on Black's Q-Side together is the precariously placed Bishop on d5. If only that were to be removed then think of the possibilities for our g2 Bishop on the long diagonal.

The initial fork of Rxc6, Bxc6, Qc4+ is quite easy to spot (although it took me a few seconds as I'm not a particularly competent player). Without seeing the Queen sac on c6 beforehand it just feels right to look into forcing the King to b7 because of our g2 BIshop aiming at it. Most of the rest plays itself at least for me.

Another note is that 6.Kd2 could be hard to find for some because when calculating tactics it's natural to only look at aesthetically aggressive moves like checks and captures. How I found that move was by taking a step back after finding no forcing moves that work. Then taking a note of what squares the King could and couldn't run to. After noticing e3 and c3 were the only squares left to run Kd2 is easy.

Overall I'd say the book got it right considering the "certain initial chess knowledge is assumed" part. I don't know about the rating part though. OTB maybe 1500 level? So intermediate with a bit of knowledge. Nothing advanced.

#11 yes probably about 1500 level. I think of beginner as up to 1200 level.

On chess.com, most 2500 rated puzzles are easier than this. This one requires you to find a silent move deep into the combination.

Of course, most players just go for the queen sac without figuring out what to do after that.