The "F" line represents Favorites List Quick Keys. The digit immediately to the right of the F represents the first digit in the FLQK number. So F0:1 with the 1 blinking, means the Favorites List with a FLQK of 01 is the Favorites List currently being scanned. Non-blinking numbers means the FLQK is turned on, not being scanned at the moment, but will be shortly.
There are a few other things too for those spaces to the right of the colon sign (the second digit of the FLQK). An asterisk (*) means FLQK is turned off, for example F1:01*3456789 means FLQK 12 is turned off. A dash (-) means there is not FLQK assigned (as in F2:-123456789 means there is no FLQK with a number of 20.)
The "S" line is something like the above, but is System Quick Keys. So if you see F0:1 with the 1 blinking and S0:1 with the 1 blinking, that means the system with a System Quick Key in a Favorites List with a FLQK of 01 is being scanned at the moment.
Number Tags are optional things. You do not have to use them, but if you do they can be very helpful to "jump" to a specific channel. If you are on Police A1 and want to go to Fire D9 real fast, number tags might be a solution - certainly faster than scrolling through the channels.
The only hitch is it takes a good memory to remember all your Number Tags. I've got several hundred frequencies and talkgroups programmed in my scanner. However, I've assigned number tags to probably less than 25.
Typically my Favorites List Number Tag is the same as the FL Quick Key. System Number Tag is same as the System Quick Key. So the only thing I needed to be creative with was the channel number tag.