blind stealing a little help
 

i am a bit confused about EV i kinda figure its the risk vs rewards of pushing a hand but would be grateful if someone could explain this to me. i used to have the problem of not stealing enough blinds on stts and so therefore not placing as much as i should but of late i have hit the other end and find it hard to control my pushes in the last 4 or 5 i know there is a program which explains EV pushes( could someone remind me of this please!!) also i sometimes find it hard to play flops after a blind steal if im called and i miss the flop, any info would be grately aprreciated.