Right hand movement is the physical action that actually equates to strumming. In its most simple form, there are two ways to strum the strings with your right hand – down and up. There of course are other variables which we will look at in other lessons (such as string selection and dynamics) but essentially you can strum the strings in a downwards direction and an upwards direction with your right hand (I’m assuming for the sake of simplicity that everyone reading this is right handed).
A good exercise to do is to pick up a guitar and finger a chord with your left hand. I would recommend playing a chord that uses all 6 strings, such as an open E chord. Once you have the chord ready, simply strum down, then up, then down, then up etc. Try to be as consistent and even with your timing as possible. This is the basic action of strumming. If you can’t do this, you need to keep practicing it until you can, before moving on. Don’t worry if the sound is a little inconstant or sluggish. Of course, we ultimately want evenness and groove, but this will come.