hi @IvanPalm welcome to the community.
usually the motivation comes other way round - by using some application you try to achieve some goal. This might be a wish to get rid of using big tech services or learn things. Depending on your goal the way differs. This is exactly the point why apps exist - not everybody need the same functionality and people customize their instance depending on their requirements.
If you don’t have a goal and just want to learn running your own Nextcloud, the guide provides very good recommendations:
I would definitely recommend you learn how to use and how to operate your system. and definitely recommend some exercises before you turn into “production” - brake things and recover to verify you have proper backup in place and you know how to restore this backup.