When creating a post, there is the ability to add one or more labels (which are considered "categories"). See my tutorial about creating a post: https://www.blogsbyheather.com/2008/07/how-to-create-a.html
For example, you just created a birthday card you want to post to your blog. You inserted the image, the recipe, and your notes. At the bottom of your post where you it says "Labels for this post", and you wanted to "categorize" this card as "Cards" and also as "Birthday" then you would enter both labels (Cards, Birthday).
As you continue to post and add more labels to your projects, then your "Labels" list for your sidebar will grow automatically with each post.
To show the Labels List on your sidebar:
- Login to Blogger
- From the Dashboard choose Layout
- Add a Page Element
- Choose Labels.
- Then, from this pop-up window, chose a title for your sidebar item, such as "Categories" or mine is called "Posts By Category" but you can name it whatever you like.
- Click Save.
- Now the new Page Element has been added to your blog’s sidebar, most likely at the top.
- Click, Drag and Drop where you want to move the element to on your sidebar.
- Click Save and your new layout has been saved.
- View your blog!
So, how this all ties together.
If you created a post that is a tutorial and put "tutorial" as one of the labels in the post, then you will see "Tutorial" as one of the categories! Then, when a user/visitor to your blog clicks on this link/category, they will be brought to a page for all the tutorials you have posted.
Here are some Blogger Help files as well:
- How to post: http://help.blogger.com/bin/answer.py?hl=en&answer=41378
- Using Labels: http://help.blogger.com/bin/answer.py?hl=en&answer=44498
- Arranging Page Elements and adding a new Page Element: http://help.blogger.com/bin/answer.py?answer=43708
Hope this helps!