the basic process is as follows:

1. estimate oppenent's hand range (HEManager)

2. put it into Equilator along with my cards and current board

3. note opponent's chances of folding to bets/raises at a current situation (HEManager)

4. actually calculate numbers

Let's say I have 1 opponent who is in position

So first I would look at opponent's VPIP and probably my notes about this player. Doesn't take a lot of time. Finding out his range takes me to something like

http://www.pokerhandrange.com/ and consumes some time. Filling in Equilator takes even more. And finally calculation itself may take an eternity and will look something like

EV(bet)=pot size*chance him folding + possible outcomes of him calling*chance him calling

while these outcomes also need calculations..

I'm probably doing something wrong as this process is not applicable to a live game