I've to write a homework in english about the neoclassical model using a figure and explaining voluntary and involuntary unemployment. please help

this a wide-open question, of which people have written books.

I guess I would start with a simple labor/leisure model (wages on the y axis, hour worked on the x) and then expand into a general supply/demand for labor. Then show some shocks to the system and show how those shocks affect voluntary and involuntary unemployment.

I or others will be happy to critique your work.