If a match has been created and a video uploaded to it tagging can start.
Click on the tag-icon behind the match.
Below the videoplayer one can find the tag buttons.
This is the record button: 
It works just like recording a video on a smartphone.
Click on the button when you see something you want in a clip.
The button changes into: 
If the end is reached of the fragment you can click the button again.
One is asked to give the clip a name and to pres "OK".
Advantage of recordbutton:
- Length of clip can be determined by user, not pre-defined.
- Just one button to click
- One can attach a name to the clip
Disadvantage:
- More work when tagging a lot.
- Be aware not to add a complete 'chat' to the name of the clip otherwise it will be very confusing. You the chat function of playlists instead for this.