Allow me to elaborate:
To create a UV-map you must select all your faces in Edit-mode, which can be selected by clicking on your model's edges, vertices and faces info in the right list. Or going by selecting it on your down left bar:
IF you would want to work with individual faces' texturing you should consider choosing to mark seams on all of your model's edges. You can do so by clicking on Ctrl+E in edit-mode and selecting "Mark seam". However, for this specific model I would not recommend you do so:
Instead I suggest you Unwrap your model directly. In edit-mode, when you have selected all faces (do so by pressing A or manually box-selecting your faces with B) press U. Your first option in the list will be to Unwrap your model. Press it and wait for it to process:
Why I say this way of unwrapping is better for you is because your specific model is created with the thought in mind that all polygons are connected to each other in a flow-like emotion, like a flower pedal.
Next step is opening up "UV/Image editor" by following these steps:
1. Remember to have all of your faces selected in edit mode when opening up your UV-mapping section.
2. This is where you can drag open a new window where you can see your UV/Image editor.
3. Down here is where you'll select the editor.
4. This is where you'll find your desired texture that you wish to use. Just open the folder and find it!
You'll see that the UV-mapping here are shaped just like your model's flower pedals, this is the intended effect in your texturing process as you did not mark the seams of your model. It will help you a lot with texturing.
From this point on you can select vertices and edges in your UV/Image editor to move your texture-mapping around to make it fit your texture properly.
Lemme know if anything else seems unclear.