Internal liquidity to external liquidity

[Heteroskedasticity]

Internal and External liquidity

Hello to all. I have recently been introduced to the concept of liquidity, and more so internal and external liquidity. It is said that price moves in cycles between the two, but I have noticed through backtesting that price sometimes goes through two imbalances then pivots to an external liquidity. My question is how do you gauge with sufficient confidence if it’s targeting external or internal liquidity, and on which side (buyside or sellside) ? thanks