Custom User Models in Aspen Plus

I’m trying to simulate a purifier in Aspen Plus in a cryogenic system. This purifier is just meant to change the pressure of the outlet stream based on the inlet flow and pressure (we are using the purest xenon money can buy and making it several orders of magnitude purer, so I’m just modeling it as pure xenon hence the purifiers only being pressure changers). I have tried using calculator blocks around different components (namely compressors and pipes) but none are allowing me to simulate a pressure drop the way I’d like. I figure the correct way to simulate this pressure drop would be with one of the custom user models, namely User2 (I’ve been eyeing it because I already have an excel sheet with the relevant formulae), however I’m sure any user model would work. I’m not exactly sure of how these user models work, however. Could anyone walk me through how to create a custom user model in Aspen, or point me to a tutorial? The section of the User Models documentation relevant to User and User2 hasn’t been especially helpful to me.