Adding Tags???

I’m relatively new to the whole blogging scene and was reading that adding tags to your writings will increase viewers. I see the right panel and where it says “Tags”, but am unsure if I’m doing it right.

So veteran bloggers, do I have to add a hashtag to the tag as I add it, or not?

I also see on the right panel “Categories”…are these the same thing as “tags”?

Do you have any other suggestions for adding tags to your blog entries?

Just looking for some help here….

David Lee