Most of the elements (icons etc.) have hidden information - when you hover on them, an info-box will appear.
Some less important and less popular markers will appear after inreasing zoom level.
Visible from levels:
Here, when you hover on an icon, you can see marker's description.
On the map, when you hover on a marker, you can see its name.
When you click on it, you'll get a box with full info about this marker (which can contain graphic or text links to external sources).
When you click on name of the airport in the box, you will get a set of points related to this airport (spottings, units, others).
When you travel from one marker to another, you can find an interesting place, which is not marked.
Then you should go to the next chapter of this help.
To be able to add and edit markers, you have to create an account in application.
What you need is a unique login, secret and save password, e-mail address and some free time.
After you fill and send registration form (topmenu->settings->register), an activation e-mail with unique link will be sent to confirm your address.
When you click the link, your account will be ready to log in and add a lot of interesting markers, what is described in next chapter.
After logging in, you will get an extra button in topmenu.
Clicking it activates editor mode, but you can add new markers only in zoom level 13 or higher.
To check this, see top left corner for a round icon - if it is green, you are in the correct magnification.
Now, click on the place, when you want to add a marker, choose its type and fill other data.
In most cases, only type and name fields are required to add new marker (latitude and longtitude are automatically filled).