Ipad 4 presounus audio box

Hi to all.
I recently downloaded the midi guitar 2 on my ipad (4 generation) and I tried to connect my electric guitar with presonus audio box iTwo but only the mic on the ipad was working with the midi guitar. Please help.
Do I need to buy anything else?
Can I use the midi out from presonus audio box iTwo to control external keyboards?
Thank you all.

Left top of screen is the audio selector. Clicking on that will bring the input selector.
If your interface is not selectable, then your interface is not connected properly to our Ipad, or your interface does not support ios usage out of the box.
Please check with the Presonus audio box user manual.