If you are using WebI check the appropriate PRM file how your date input is actually defined. From your posting it is not evident what format you are expecting as the example could either be 1st Aug or 8th Jan. The data indicates however a European format.
You can find more information using search for how to manipulate the PRM file (and having a backup of the original is worth having).
Once you manipulate the PRM file this will set how the dates entered are interpreted.
More information can be found in https://bobj-board.org/t/84923.
As for the prompts check out https://bobj-board.org/t/198038 - essentially you do two variable date prompts .
Alternatively and more difficult is you put the filter logic straight into your universe design. If your data coincides with my assumption that for each STOCKS there can be only one MATERIALS at a point in time then you can create a filter where the STOCK.Date (is) Between MATERIALS.DateFrom And MATERIALS.DateTo.
If this filter is applied then selecting from STOCKS will only show the MATERIALS relevant for this stock record. If not applied it creates a Cartesian product between STOCKS and MATERIALS.
Depending on your users’ knowledge you might have to set this filter as a default selection for them. But that’s a different topic.
KMB 
(BOB member since 2004-02-11)