How to Label Your Blog Posts:
Step 1: Go to your post section on your blogger dashboard and click "edit" to edit the blog post you want to label.
Step 2: Under the labels section at the right, add a new label name to this blog post. You can add more than one label to a post by separating them with commas. Then click done, followed by update.
Step 3: Go to the layout tab on your dashboard, add a new gadget, and then scroll down until you find the gadget called Labels. Click the + sign.
Step 4: Choose how you want your labels to appear on your blog, and click save.
Step 5: Drag and drop the gadget you just made, to where you would like it to appear on your sidebar. Then click save arrangement.
Step 6: View your blog to make sure you like the placement, and the way the widget is laid out.
Step 7: Bonus: For you can click each link in that list to see the entire feed of posts with the label football, for example. I suggest taking this one step further, and making snazzy buttons for your sidebar that link to all posts with that label!