Linking drop down list to select from another list ?

Hi guys

My brain is melting here trying to work out how to do this!

The attached spreadsheet will hopefully clearly show what I am trying to do. Basically, I am creating a calculator and have stumbled at the first hurdle! I need a drop down list of habitat types which I have acheived, and then a second dropdown list which has a bit more detail about the type of habitat - depending on what they chose from the first list. Hopefully the background data sheet which show how I am trying to do this with the 1st row being the options in the first list and under these and list of the options from that selection ...

I hope this makes sense.

Thank you!
Si

Developers Biodiversity Offsetting Calculator.xlsx

Debra Dalgelish shows how to do it on her website, here:

http://www.contextures.com/xlDataVal02.html

Hope this helps.

Pete