I can't use my mouse properly to play

I'm on minecraft pe Android, so I wanted to put a keyboard and a mouse to play more easily and the problem is that I can't use the right click or the wheels or other button on my mouse. I can only use the left click so to undermine I keep pressing, to pose I press once etc. But to turn the camera I must stay pressing on the left click it removes the practical side of the mouse and keyboard.