Hey there, and thank you!
I would be ill-equipped to give anyone music lessons :) Besides, with Bosca you cannot create just about any kind of music. Bosca Ceoil is a step sequencer, your music will have a distinct rhythm to it, which you cannot escape. Orchestral music that you reference, from Sunshine and Inception, is simply impossible here. You’d need a much more powerful DAW to have that level of control over the melody and composition.
Bosca fits a particular niche. When getting to know it, I think it’s better to approach Bosca not from the perspective of “I want to realize some very specific idea from my head” but rather as a box full of classic LEGOs. Akin to a step sequencer, you are working on a grid with LEGOs, yet you can create some impressively complex structures after gaining some experience. You need to learn the limitations and what the tool can achieve, which will shape your ideas for what you can make with it.
It’s not a limitless tool (as if anything is, right?), but it’s also not overwhelming. You have few simple rules which you have to follow, but that can be good for creativity in certain ways. Once you learn what this tool can do, you can be efficient at solving particular problems with it and getting the result in the niche that this tool excels at.
Cheers!