Relationship between difficulty and network hashrate

Is someone can help me to understand the fomula that explains relationship between hashrate difficulty time of block and block reward. So i need to understand it as for bitcoin for example there is strong relationship that described here:

So it is very helpfull to understand!

thank you!

Roughly speaking, the mining reward one gets scales proportionally with one's hash rate H and the block reward B, and scales inverse-proportionally with the current difficulty D. I think this should be the same across different cryptocurrencies including bitcoin and zcash.