Indent/Unindent - it moves text to the right or to the left on one tabulation character or some spaces (look at Preferences, Editor page). For an indent you can also use a TAB key. Both of functions works with a single line or multiply lines as well.
Append to the Crapbook - add the selection to the Crapbook. It's not important that Crapbook is opened or not - this function works in any case.
Swop - swap the selected text with a clipboard content. I.e. text from the selection moves to the clipboard, and at the same time the content of clipboard is moving to the place of a selection.
Move line up/down - doing that. Please note that there is no need to select a line. The operation works with a current line (where the cursor is placed).
Mark. Mark is a special selection mode. It gives you the ability to select text multiply. To mark some text, select the text normally and apply Mark. To "deselect" the marked text, point to it with the cursor and use Mark again. The another way to disable marked selection is the Unmark all menu item. You can copy all marked text using Copy marked function.
Copy all - copy all text to the clipboard.
Copy current URL - before using that, you must point with cursor to the URL at your text.