Where to connect object pin from cast to node?

I don’t know what kind of object requires in order to make my cast to node working in the right way. The blueprint I want to cast to is a Task name of AI_Patrol used in behavior tree, and its parents class is BTTask Bluprintbase. The blueprint I want to use the cast to AI_Patrol node is a service node used in different BT. Basically its job is to figure out if the task node is executing or not. However I do not know what to connect for object pin of cast to node. What do I connect? I will include some screenshots.

I updated your attached image.

This might work for you. But you should watch some tutorials on AI to learn best practices.

I couldn’t find that green one so I had to use blue one instead. I don’t think it is working. I tried to find a tutorial that explains how to use that Is task executing node but I couldn’t find one.

Why do you think you need to use that node?

So I can access the behavior tree using that task?