I like Kara Andretta’s tutorial, but there are many different ways to achieve a realistic rose. Use whichever feels most natural to you.
https://www.google.com/search?q=Kara+Gumpaste+Rose+Tutorial&rlz=1C5CHFA_enUS708US708&oq=Kara+Gumpaste+Rose+Tutorial&aqs=chrome..69i57j33i22i29i30.16256j0j9&sourceid=chrome&ie=UTF-8#kpvalbx=_3NgFYYDDHdi1tAajkZr4Cg57
Sugar Sugar by SSmiley