Wood Baby Gate How To Attach A Baby Gate Question?

How to attach a Baby gate question? - wood baby gate

I need a baby gate at the foot of the stairs now, from my little girl one years who has just discovered he can not climb setting. My problem is that it reached a wall on both sides of the stairs, a door. The wall on one side and the railing on the other. Start an iron fence, I saw some wood. Has anyone any idea how to operate a door in this situation?