Hi Elena! This may sound a bit technical but try to follow along as best as you can.
For a side kick, transfer your weight to the supporting leg. Then pull up the kicking foot to a position just in front of the knee of the supporting leg. At the same time that you are pulling up this foot, pivot the supporting leg's foot so that that heel of the support leg faces the direction of the kick(this process is referred to as chambering your kick). Strike out quickly to the side of the body(referred to as your snap, but don't lock out your joints), and quickly return(or recoil) your foot to the chambered position and then place your foot on the floor again. TIP: As you are pivoting your support foot in the chamber phase, rotate your hip directly into the direction of your kick. Hope this helps!