There are different demonstrations discussed here which will start from the most basic to the most complex ideas. How to paint lilies, tulips, dahlia, roses, even a southern magnolia and bouquet of flowers are included.
You might have gone out and bought a huge fresh bouquet of different flowers from your favorite florist. I see that you might be excited about these flowers to paint. Your excitement is understandable and we are getting excited too. So, when you get home, you cut off their ends, place them in a vase arrange them to their proper positions and you might directly go to your shop or paint station and start painting.