Meetings are further divided down to two types: Mandatory Meetings and Optional Meetings.
Mandatory meetings are special meetings that occurs 7 times each year which takes in place of an optional meeting and will tell you about what is happening in the next 1-2 months. These meetings are very important, and in order to get certification, you cannot miss more than 3 of these meetings without prior approval by an officer.
Optional meetings occur every Thursday, starting at 4PM, and taking 45 - 60 minutes, these meetings are just time to play and discuss chess with fellow members. In addition, if you want a leadership role, it is extremely recommended for you to participate in these meetings.