Have your feet underneath your hips, stand tall and activate the muscles through your upper back and stomach to hold a neutral spine throughout the movement.
Starting with one side, step forward keeping that line of foot and hip. The distance will depend on how long your legs are so if they’re truly long like my own (I happen to be ‘average height’, and I’ll continue to claim that…) then you’ll need a longer stride than some, about 1 metre should do it. Drop down through the knees and allow some forward progression of the front knee over the toes. Whilst staying tall through your torso, drive up and forward through the front foot, using the muscles of that leg and glut to get you back to the starting point and ready to repeat on the opposite side. Start with your body weight and add resistance when you can handle it, either a bar on your back if flexibility allows or simply hold some dumbbells.