All the app controls are vertically arranged in the column on app left in compact or extended view, mouse click on any button toggles controls column view between compact and expended.
    As soon as new job starts by opening new image file or reopening current one, app creates list of pages to be printed out using requested paper size, printer margins and overlaps based on current image size.
    In poster creation mode app splits the source image based on requested paper size, printer margins and overlap, only. App does not try to split source image in identical by size printing segments, as a result, printable segments may, and most likely will, have different sizes on different pages. Printing orientation (Portrait/Landscape) is determined by source image orientation.
    In poster creation mode purpose of overlap is to provide area user can use to combine all segments together, e.g. to glue those segments together.