Welcome, Obi2winky. Getting started is a good question. When I started, I started where most don't, though I had helped friends in my teens who were putting cheap kits together for deer season. As others have suggested, kits are a good place to start. The first rifle I actually built though, was not a kit, but just components. The great advantage to a kit is you have all parts picked for you, much of the woodworking done, and a set of instructions. If you have any doubt about your skills, go with a kit. I would rather see you have a functional gun than getting discouraged and never completing one. But it depends on your skillset and determination too. I have seen some beautiful rifles made from kits, with a little extra work.
However, if you choose to build one of your own design, you will need to come up with a plan, accumulate the necessary parts or make them yourself, and get a block of wood to carve into a stock. My point is, you need to assess your own skills, and what your goal is. Do you have strong woodworking and metalworking skills? Then maybe you want to take my approach with my first. If not, maybe a kit would be better for you. I have a forge, and could easily make my own locks, but working alone, it would be difficult for me to make my own barrels. Just depends on your situation. I wish you luck with your build, and you know where to come when you hit a roadblock, which I am sure will happen as a new builder. I just wish I had this resource available 24 years ago when I built my first.
M. E. Pering