To be honest, I've never heard that saying before. This is how I understand it: If you make a plan ("hatch," like an egg hatching) and do something harmful, don't be surprised when you experience ("catch," like catching a ball) a harmful result yourself. I hope that helps!

A bad start(or whatever you put in) goes to a bad outcome, you harvest what you seed. this proverb has an atypical structure (prepositions are omitted)

I've never heard this.