ipad display rotation locked

I bought this programme yesterday and am still trying to get to grips with it, so apologies if this question has been asked before.

I have an ipad mini and the display only seems to work in landscape mode. The chord symbols are on the right hand side and the list of songs shows on the left hand side. My eyes are not what they were and I should like to get a full screen display of the chord chart, preferably in portrait mode.

Can this be done or are new spectacles required?

With the unit vertical (portrait) -- home button at the bottom, check the tiny slide-switch at the top of the right side (edge).
In the iPad's SETTINGS > General, that switch can be configured to lock screen rotation in either landscape or portrait mode or permit auto-rotation with the switch "off".
:))BOB

Many thanks. No need for new spectacles.