E.g. the timeframe for a match of you is 1.3.-5.3.
Then you open a thread called "matchday 2: (your name) vs (other name)".
Then you write in this thread.
This is how you should write a message to arrange this match:

"Hi xy(name of your opponent),
I have time to play this match on 3rd, 4th and 5th, 18-20 o clock."

Then you wait that your opponent answers to your suggestion.