Screem has a very wide range of useful features, and probably some not so useful ones :-)
The following section of this manual describes in depth each of those features, along with any currently know bugs so you know how to avoid them while they are being fixed
As can be expected in any reasonable editor multiple pages can be edited at once. Notebook tabs for each page are present below the editor window, and can be switched between by clicking with the left mouse button. Clicking on them with the right mouse button will present a popup menu allowing you to do the following:
Save the page
Save the page as a different filename
Close the page
Rename the page