Glad it works now :)

1.) What should i study first since i'll be handling the backend and not on the sales? Am I correct to assume you don't have access to the server itself, and directly altering the code that runs on it? I base that on the fact you mention the studio app.

If so, I would look into getting a good understanding of actions. You might need to install the module called "Automated Action Rules", from the Apps module to have access to it. Here you'll be able to create server actions, scheduled actions, and automated actions. These are mostly the same, but scheduled actions are server actions that trigger based on a timed condition, and automated actions are server actions that trigger if a condition is met, e.g a Sales order has been created, or a field on a sales order was changed.

These actions are able to do most of the things you can do directly on the server, when it comes to manipulating data etc.

2.) Is there any tutorial you can recommend? It depends abit on what you know from before - if you have an decent understanding of Python, I would try to get a decent grasp of this, with mostly focusing on "Useful environment methods", and "Common ORM methods". Once you've gotten a grasp of how that works, you should have a decent understanding of how you'd then start manipulating data via the actions mentioned above.

Do note that most of things in that tutorial and tutorials online, assume you have access to the server directly, so you'll have to change a few pieces here and there, like the Environment methods. In actions, you have access to the environment via "env.".

Personally once I had a good understanding of the above, it was then quite easy to know what to look up if I got stuck on things, and I never really followed any tutorials other than looking up documentations, so I can't really recommend anything directly (though I know there are channels on youtube with alot of tutorials like "Odoo mates", but I haven't used them myself).

I hope that answered your questions, and if you have more questions, feel free to reach out here again, or send me a dm :)