When you register on the forums you will be placed in the “New” user-group which means you cannot have an avatar or your signature displayed in addition to only having the ability to save 10 private messages at a time.
Once you pass 20 posts and have been registered for more than 20 days, you will be promoted to the “Registered” user-group. This will allow you to pick an avatar (go to the control panel > edit avatar and pick from the selection available) and have your signature displayed. You will also then be able to save up to 20 private messages.
Once you pass 40 posts and have been registered for more than 40 days you will be promoted to the “Registered*” user-group. This will enable you to upload your own custom avatar (go to the control panel > edit avatar and scroll to the bottom section "custom avatar"). You will then also be able to save up to 50 private messages.
Please note: promotions are not done automatically, they are checked every 24 hours, so once you have reached a certain amount of posts, please wait 24 hours before you are promoted and gain the privileges associated with the user-group.