If you're running on a Windows machine you can install a PDF "printer" such as CutePDF or doPDF. You can find these, and other options, by searching for "pdf printer" on your favorite search engine. Once installed it will appear in the list of printers on the print dialog box along with whatever other printers you have available.
As for your second question "editor and main window don't merge together..." I'm guessing that the editor window is "undocked" (it appears as it's own separate window). You can redock it by clicking on the down arrow button in the upper right corner and selecting the "Dock Editor" option.
Hope that helps