So, when it comes to using HTML nowadays you wanna think about the separation of content and style, so elements like <i> or <b> are a bit problematic. They mix style with content.
Instead maybe look at this pdf
https://websitesetup.org/wp-content/upl ... -Sheet.pdf it seems to have fairly good descriptions of the different tags, what they are used for, when and why.
You should only use html to describe the content as informatively/semantically as possible. Any effort to make your website look a certain way should be done with CSS. (the same site has a cheat sheet for css but it's much more dense and less educational
https://websitesetup.org/wp-content/upl ... -gdocs.pdf)
Another good way to broaden your skills is to take the courses offered at BTH in just these subjects. See:
https://dbwebb.se/kurserOr if you have any more specific questions you can join the IRC:
https://www.student.bth.se/kiwi