Hiding Row depending on Drop down list

Hi,

I have a spreadsheet I am trying to create where I have a range of 7 different values in a drop down list. What I to happen is when I select a certain entry from the drop down list that a number of different rows on the spreadsheet will be hidden depending on the entry selected from the drop down. Trying to get it to do this automatically when the drop down selection is changed. I know this is to be done through VBA but a bit of help as to how to start getting this rolling would be greatly appreciated.

Many Thanks