hello. i bought some new brakes 3 days ago and when i installed the new ones they are real sqeaky. sio loud that it hurts my ears or anyones around me.

i tightned them and everything but i did notice one thing the left brake pad is not fully touching the bike when i push down on the brake lever. only the back side of it touches the wheel is that a problem? if so i can i fix this? i tryed everything should i just go out and rebuy some smaller breaks or something?
its a 15 speed roadmaster and it's black i had it for 6 years and everything was fine intill i changed the breaks now they dont even work