Transitions are part of Explaindio 4 PRO Creator Pack which loaded inside your Explaindio 4 Software Libraries by the API when you Validate your Explaindio API. So, please make sure you've correctly validated your Explaindio API.

So, if you don't find any Transition inside your Explaindio 4 Software, that means:

1. May be you didn't buy the Explaindio 4 PRO Creator Pack. If you haven't already, please consider buying Explaindio 4 PRO Creator Pack to get the Transitions inside your Explaindio 4 Software. 

2. Or, May be you didn't validate your API correctly. In that case, you may follow the instructions in this support article to correctly validate your Explaindio API: