Once you've arranged with your opponent a date and time to play your match in any given round, you can publish that. That is good for keeping track yourself, as well as allowing others to spectate (live watch) your match.
You can find the calendar of published matches
here, if you want to spectate yourself.
To enter a planned match, you need to enter data into this
google form.
Choose "Add" to add the match, then choose "ShuffleIT Championship" for the Tournament, then enter your and your opponent's name. Set the start date and time (remember to convert to UTC) and set the match length (1h 30min or 2h are realistic values).
If you then update the first linked page, it should show your match now.