I don't know if I can quite describe this effectively, but I am greatly struggling with networking concepts.

I've looked at videos on YouTube and resources provided by my instructor, and yet it is somehow just not sticking... I'm not really sure what my steps should be, and if I'm doing things right or not.

Normally I'll find some sort of calculator which I can use to input my problem and I rely on that to tell me if I did it right. But the issue is, I'm getting so many different results online that I can't find one that gives me any sort of confidence in the work I'm trying to do.

Any resources that might be able to help at all?

Keep in mind, I'm the kind who struggles with abstract concepts, such as ones in advanced algebra.
If I can't mentally comprehend how something works, most times it will make me feel stressed and lack confidence in what I'm doing. So if there's any material that can word it in a very straight-forward way, maybe with examples, or visualizations, that would greatly help me!

Thank you very much for your help.

https://preview.redd.it/7b85j0ar4r3c1.png?width=1700&format=png&auto=webp&s=8bbff8b0a01419fd818115ffb77a302d99022d76