The first knot is a half hitch knot and if they are spaced apart, they form loops or flower petals.
Make 10 or 12 loops, depending on the yarn and flower size. The pull the yarn carefully through the loops and close to form a circle. Tie and you’re done.
Sometimes moving pictures make it easier to learn, especially a movement related technique like tatting. I watched this video by TotusMel to learn how to make the knots.