Filter by Tag for Blog
Go to Blogs > Choose Blog Pages

1 - Show all / Manually blog

1.1 - Disable

Choose disable this filter for undisplay.

1.2 - Show all

Enable this feature for show all filter Tag

1.3 - Manually block

Choose manually block and add Tag to content.
Add tag to content box
Source of tag from here:

2 - Show count

Count only show all. Not working manually block.