Welcome! Great choice of manga!
If you're asking how to make a scanlation of a manga, there's a lot to that - the
English language Wikipedia entry breaks that process down at a high level.
I would suggest starting by looking at the groups that are doing scans in Czech on the site now, and seeing if some of them have ways to reach out and make contact (websites, discords, etc.). Some scan teams are willing to take beginners on and teach them the basics of the process, so if you can find one that would do that for you, that would be a great place to begin.
The other obvious place to begin would be learning Japanese, if that's something you can pursue, though for a single manga that might be excessive. If that's not a good option, you may be able to do a secondary translation from the English version instead, since it appears you have some familiarity with that language.
Once you have a finished chapter,
this thread in the Tutorials section gives the basics on uploading that chapter here. The Support channel in the Discord is a good place to go with any questions that may come up once you've gotten to the point you're ready to upload.
