Picking and Grabbing Objects from ground

Upon firing a Montage Notify, I want the character to grab an object.
How do I make it so?

I found a tutorial, but it only uses IK and I don’t know if there are any other ways.
Furthermore, I need to recognize if the object is on the floor or midair, but how do I check if it’s on the floor if the object is staying on a desk, for example?