Here are some steps you can follow. More detailed description and photos will be below.
This image shows the first two steps. Each angle uses different circles. In your sketch, it may be helpful to draw a light curved line where the highlight is.
This picture shows the final steps. You don't have to lightly erase your first sketch if it was light enough. For shading, you can usually shade each 'circle' as if it was a circle, with where the shadows and highlights are. Of course, it will not be exactly the same, but this can be helpful. I will say it once more, USE REFERENCE. If you practice using reference, eventually you will not need it to draw a nose, but reference is always helpful.
I hope this article has helped you. Noses are pretty difficult, but I hope this gives you somewhere to start. Keep going! God bless!