What was the first step to becoming a guild member?

Most guild you can join simply by clicking "Join Guild" on the left sidebar.

If the guild is private, a member will need to invite you before you can join.

If you go to the Guilds section on the Neoboards and create a new post saying that you are guildless/looking for a guild to join/etc., you will almost surely get many responses from people that would be happy for you to join their guild.