You can let the group know that you plan to attend a future event by going to My Stuff → Sign-Up For Upcoming Events.

This will display all of the events other than meetings that are on the calendar in the days ahead, as shown below.

Click on the Sign Up button next to each event to update your registration status for that event.

This will take you to the page shown below, where you can sign up any members of your family for this event.