Formula to Show True False

Hi Everyone.

I hope someone can help me.

I have attached a part of a worksheet used at work. It shows when an individual starts a course and when they finish the course.

It also needs to record if individuals leave the course either before a 3 month period, between 3 and 6 months, between 6 months and a year or after a year. The relevent boxes need to show True or False relevent to when they left the course.

I need formula's to show a return of True or False in Columns F,G,H and I when an end date is recorded in Column J. I have no knowledge of Excel formula's at all , Someone started on this but left and I'am stuck with what I have here

Can anyone help at all.

Thank You in advance