If this then

I want to create a scenarios. ie. “If this then show that”

eg. A user has submitted 3 forms for the day, I need to alert him, that he has run out of credit.

You could create a counter in the sheet that would fill a column value if the count is >= 3 and then display that column somewhere in your app. No option for logical conditioning and a pop up message within the app though.

Have 2 sheets, Users and Answers. The Answers sheet will have a record per user post. The User table you make an extra column “Count” and use a SUMIF with a reference to the Answers table. (make sure to use an Arrayformula).
Then another column with the Modulo of the SUMIF value. If you do a Modulo 3 then every 0 value is the 3rd value. You can use that value to make an IF statement in another cell as text to show the user.