Need help - trigger ,,redstone on,, keep spawning entities

Hello

I'm working on mode portal + portal 2 to minecraft and I want to make a blue gel dispenser that spawns entities (blue gel) when the redstone is turned on. But I absolutely don't know how to do it. I tried everything I could think of, but each time only the entity turns on after turning on the redstone (I have a blue gel as an entity and when it falls, it turns into a blue custom carpet (blue gel) with a jump boost effect). I found one person who made a gel mod from portal 2, I saw how his gel dispenser works. After researching, I probably found out how he did it, so I tried to put it in the "redstone on" trigger, but it threw me an error.

I have a version of 2021.1. I know there is a newer one, but since I'm doing a mod on version 1.12.2, I have to work on this version, because newer versions of the mcreator program don't support this version.