Start by typing /pr in the bot channel and the "/prop mlb" command will pop up. Click on it.
Different options (3) will show up. You must enter something into each of the 3
The 3 different parameters are:
player: get data for a specific player
market: filter the output based on the market that you wish to see (Hits, RBIs, Runs etc)
side: Choose to see data for the Over or Under