Open the document editor by pressing the thumbnail grid icon in the action bar.
Make sure you are in the edit mode. To switch to the edit mode you have to press the edit button at the bottom.
The floating edit button will have changed to a plus sign.
Select one or multiple pages in the thumbnail grid. Selected pages are marked with a colored check mark. The actions will be enabled as soon as you have a selection.
Press the delete button. The selected page will now disappear.
Press the confirm button and choose a save option.
Note: Any changes that are not confirmed and changed will be lost when leaving the document editor!