At this stage, you want to start to create some interest in the reunion. The more content that you can put on the website the better. Classmates who visit the website will see that you are serious about the reunion and will help to spread the word.
You should post a message that tells visitors you are in the early stages of planning the reunion. Invite everyone who visits the website to register on the classmates page and to tell their friends about the website. Encourage people to come back often as there will be many updates in the coming weeks and months.