hello, I hope this is in the right section.

I`ve been reading pretty much about data modeling, entity tables, attributes, keys and such things.. But when Im gonna create a database for something Im still not sure what tables I should create.

Is there any right or wrong table in a solution? Or can I choose by myself what tables I want.

You should try and take a stab at it. Just remember to try and stick to a normalized ( at least 3rd NF ) structure.

Most businesses have employees, customers, a product or service, and invoices (and its LineItems) known as the big four. Then there are support (or lookup) tables which may be the 'many' side to any field within those tables. If you find yourself adding 'like' fields (such as Monday, Tuesday ... Or staff1, staff2, staff3) they should probably be in related table.

As John says, give it a go and you can always post your skeleton structure file showing entity relationships for review as you go. :^)