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 ending at 5PM, 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.