Report Builder - How to create a #orders by week report - must a change the model

Question

Hi

Say I've published a simple report model with only one table:

SalesOrders (OrderId, Date, Type (A or B), TotalAmount)

Can a end user using Report Builder create the following graphs:

1. A graph showing weeknumbers in the x axis, and number of orders in the y axis as two series (A and B)?
2. A graph showing weeknumbers in the x axis and the summarize totalamount in the y axis

(if yes, I'll be very happy if you could provide me with a link to an example, or even better outline the steps involved)

And, if not, what should I do with the model to help him achive the result?

Regards

Lars