Start by saving your own opening ranges as presets in Equilab.
e.g. Suppose you typically open 66+, ATs+, A5s-A2s, KTs+, QTs+, JTs, AJo+, KQo (11.92%) UTG. You can save that as "UTG open" in Equilab.
You should do the same for each of the positions.
You can then quickly call up a range, and then input a flop, and run that range against some specific hands.
e.g. Suppose you were playing against yourself and you opened UTG with that range and called with 99 on the BTN. You can compare the equities on various flops.
Pre-flop, 99 has 51.6% equity vs that 12% opening range I mentioned.
UTG****48.41%**47.88%***0.53%*{ 66+, ATs+, A5s-A2s, KTs+, QTs+, JTs, AJo+, KQo }
BTN1**
51.59%**51.06%***0.53%*{ 99 }
It's basically flipping, but that's just pre-flop. The flop can radically change the equities.
On a flop like A72r, 99's equity drops down to 34%. This is because UTG's range contains so many aces.
Board: 2
A
7
*******Equity*****Win*****Tie
UTG****65.80%**65.41%***0.38%*{ 66+, ATs+, A5s-A2s, KTs+, QTs+, JTs, AJo+, KQo }
BTN **
34.20%**33.82%***0.38%*{ 99 }
So you learn that that flop is a good one for UTG, and a bad one for 99. (Change the BTN's hand to AQ and re-run the equities and you'll see just how strong TPGK is).
On a flop like 855r, 99 is doing better vs UTG, since villain's range has so many Ace highs and suited Broadways that missed.
Board: 8
5
5
*******Equity*****Win*****Tie
UTG****38.78%**38.45%***0.34%*{ 66+, ATs+, A5s-A2s, KTs+, QTs+, JTs, AJo+, KQo }
BTN**
61.22%**60.88%***0.34%*{ 99 }
I won't do the calculation, but a flop like A96r would be particularly good for 99 (sets are good hands, obv).
By repeatedly studying spots where you run hands against ranges, you'll get a feel for which flops are good/bad for each range. It's essential that you start with reasonable ranges though, which is why I suggest building your own opening ranges and saving them as presets.
Once you've got used to what your own ranges are, you can make estimates of what your opponents are playing. e.g. If someone much looser than you opens UTG, then add 5-10% more hands to your default UTG range, and run some equities on the same flops, to see how much they vary according to the width of the starting range.