need help with caliper/side pull brakes moving

i am trying to fix my old mtb bike that i haven't used in long time. the front side, caliper/side pull brakes didn't right. if i pull the lever, the brakes moved and unable to return to their original position unless i move them with my hand. if i let the brakes as is, once i pull the lever, other side will nearly touch or just rubbing the rim. if i tighten the nut, the lever will be hard to pull and the brakes just move the same way it did before. not sure what i did wrong. hopefully anyone here can help me solve the issue. thank you.

https://postimg.cc/w1nnxC3B