Three tables query

Hi, since I'm new to queries I have a "big" problem unless for myself when trying to join three tables. What I want to do is as follows:

I have three tables  named: sales, detailsales and items

sales relates to detailsales throuhg the key "sale" and 

detailsales relates to items throught the key "item"

What I want is a report that display the total of sales grouped by "item" included at detailsales for an specific date included at sales and filter for an specific "line" included at items table.

Hope some one can help!!

Thanks in advance