To challenge another club, first go to the homepage of the club you want to issue the challenge from.
Create the event
Go to the clubs home page: https://www.chess.com/clubs
Select the club you want, then from the admin settings on the right side of the club home screen, select 'New Event'
NOTE: you will only have this option if you are a coordinator or higher in the club. See here for info on the different club roles.
When you click 'New Event' you will be given a new menu with the many options for creating tournaments and other events, select 'Club Daily Match' or 'Club Match' from the options:
Next, select the options for your match:
Choose the settings
My Club will be a dropdown list if you are coordinator in more than one club.
Club to challenge will allow you to search for an opponent club, in put the name of the club you want to challenge!
Match name: name your match!
Game type: choose from standard chess, chess 960, a book opening, or a custom FEN
Days per move: choose the time control, 1, 2, 3, 5, 7, 10, or 14 days per move
Quick description: write a description of up to 1000 characters of the match
Rating range: if you want, set a minimum and maximum rating for players to join the match
Minimum games: If you want, set a minimum number of games a player must have played in order to join the match.
Players per club: set the minimum and maximum numbers of players needed for the match to start.
Concurrent games per player: pick 1 and the players will play one game at a time, pick 2 and they will play both games (as black and as white) at once.
Start date: put a date here if you want the tournament to start at a certain date no matter how many players have joined.
Start time: specify a time of day, the default is midnight on the start date you chose. All times are in your own time zone.
AUTO-START when 'maximum players' is reached: turn this on and the tournament will automatically start when the maximum players have joined, regardless of the start time and date.
Games are RATED: disable if you want to play unrated games.
Create the challenge
Once you've made all your choices, you are ready to click the orange 'create' button at the bottom of the page, and the challenge will be sent to the other club. When the other club accepts, the match is on and club members who want to participate can join in the battle!