You can do practically anything for a family reunion. But most reunions follow one of three patterns.
There are other, less-used patterns, such as holding a family reunion online using a conferencing service.
Although you can change your mind later, you probably already have a vision in your head of what type of family reunion you want to hold. Take ten seconds to write down your choice. It will help you focus on the elements that are important to you and save you time and confusion.