Tap and hold the first bar, then tap on the last space of the last measure you would like to select. Then tap and hold the selected area highlighted in blue.
A menu will appear that will let you choose from Copy, Cut, Delete, Insert space and Cancel Selection.

COPY - will save the content of the selected area to the clipboard.
CUT - the selected area is removed, moving the remaining part of the chord progression back.
DELETE - will clear the content of the selected cells without removing them.
INSERT SPACE - will insert empty space in the length of your selection
CANCEL SELECTION - clear your selection and start over

To PASTE it, tap and hold at the location you would like those chords and select:
PASTE INSERT - it will insert those bars
PASTE OVER - it will paste the copied bars from the the selected measure.
CLEAR CLIPBOARD - remove the currently selected bars from your clipboard