Create blocks in your own Minecraft mods?

I have a question that is not fully described above. I already know how to create blocks.

Here is the link from the tutorial for 1.14.3:

The problem I have is that on the one hand I want to create blocks that do not look the same from all sides and that I want to integrate "blocks" with more than 1x1 blocks. As an example like the bed in Minecraft which is bigger too.

And one more question about updating that there are more or less differences between the versions is clear to me, but if you just use a newer version of Forge and insert the "src" folder, it shouldn't work anyway. At least as long as it is just blocks and items without function, should that work?

Counter question: Why do you want to create mods? There are now mods for everything, so in my opinion it is no longer worth the effort.

Then tell me a mod with which you can go around with a ship, the Archimedes Shipsmod / Davincis Vessel is quite modest and the mod that I would probably take is only updated until 1.7.10

Do you want to make a mod that you can use to drive around with a ship? So if you already have a problem with modeling then good luck with programming. Sry but something like that takes a lot of time. I don't think you will have this patience.

Can you help me with my question now?

No and nobody will help you either. It doesn't just do that. You need long programming experience. Before you can do that, learn Java 1 × 1 first

I already have a basic knowledge of Java, and if you can't help me, why should you have an answer at all?