it’s really simple. it’s a condition, it says if 2 values are equal do something. you could google it and get all the information about this function. and please add some comments to your question, or search in the questions for answer, if there weren’t your answer, then post it. one more thing, when you wanna use this function in blueprint, you can put your mouse on the function and then some information will be appear. or just use ctrl+alt on the function.
check this question too.