I have 4 pages - 2x2. My question is the following. I’m, for example, in the first page (left-top), then I open pdf file by using a file manager. I’d like to open whole window with pdf file in this page. In my current configuration it is opened in 4 pages - 1/4 of file in each page. In the first page I have left-top part of window. Each time I have to move it at whole page.
This sounds like a placement style issue, what Placement style are you using? If you are using something like MinOverlapPlacement, it will place the window in an area that overlaps the minimum number of windows, which almost sounds like what is happening.
But by default windows are always started on the current page, but then placed depending on your placement policy. See the manual page for the different placement styles, you can specific these for all windows or a specific window. Something like PositionPlacement to state the exact position with Move arguments could be used too.