Hello! Yari from ThinkAndBuild.it here 
UE4 AI Perception System – with just a little bit of C++
https://www.thinkandbuild.it/ue4-ai-perception-system/
In this article I’ll go down the rabbit hole, showing how to setup and use the AI perception system. The official documentation about this topic is good but I had to scrape other needed information from various forum threads, Unreal-Answers posts and a lot of try-fail attempts. This article will condense my experience and findings into a single place! I hope you will enjoy it!