Not sure how to save excel spreadsheets I have been emailed. I need to save them in a folder in order to use them at a later date. Any help would be great. Thanks

Do you have any app installed which can handle Excel files? If yes, from within the mail App, open (view) the excel file - in the upper right corner is the (let's call it) "export-" button - tap it and "open in" that App.
There are lots of free (and paid) office apps around which can manage excel - anyway, they will not save the file into a folder as known from PC.

If you just need to store the file you may use cloud service with App - like box.net or dropbox (just 2 examples)...