Need help with spawning an entity within the player's radius (a few blocks from the player)

Sup, I ran into a problem today. I just don't know how to make an entity spawn randomly within a few blocks of the player. Im creating a horror ARG mod, but im new to MCreator and don't really know how things work. I'd be very grateful if you could explain step-by-step what blocks i need to insert, etc., to make it work.