Help please.

[curehead]

I just purchased 'Discount by quantity plug-in'  I have been playing around with this plugin and cannot for the life of me to get it to work.....

This is what I want to happen.

I have a language school and want to have people purchase courses & accommodation through a shopping basket system:

My website is www.elacademy.co.uk
If you go to 'Courses' menu drop-down at the bottom is a tab called 'TEST only'.  Here I have set up a menu link to the front page of the shop. I have set up General English 25 hrs as a course with a basic weekly price.

What I want to happen is:

• Student selects amount of weeks they want the course to be.
  Total (discounted) price for that selected amount of weeks is displayed before they add to cart.
  (One week is £350 for this product but 2-3 weeks is £312 per week, 4-7 304, 8-11 less etc etc etc up to 52 weeks.)
  
  I want the students to be able to add a preferred start date for their course (possibly from a calender selection?)
  I also want them to select a similar start date for their accommodation.

Can anybody suggest a total idiots, step by step guide for doing this for a product which has access to the discount by quantity pluggin.

Thanks so much in advance for your help, my brain is hurting after trying to do it without the pluggin and now , with the pluggin.