Step 1:
Decide where you'll download the files to on your computer. (You need to download them to our hard drive first and then burn them to a disc later). I suggest putting them in a folder on your desktop. To create such a folder, right-click on your desktop and select 'New> Folder'. Type a a suitable name (such as 'Service') and hit the 'Return' key.
Step 2:
Go to the Amazon website:
http://www.amazon.co.uk/
Search for a song and click the 'Buy' button. Go to the checkout and pay. (You can do that for each song or you can order them all first and then pay for all of them). When you're asked where to save the file(s), navigate to your desktop by clicking on the little downward arrow at the right of the 'Save in' box and clicking on 'Desktop'. Then double-click on the 'Services' folder.
Step 3:
Put a blank CD into your computer's drive and open your burning software. That's likely to be Windows Media Player. If it is, follow the instructions from number 3 onwards here:
http://www.wikihow.com/Make-an-Audio-CD-With-Windows-7
(Where those instructions refer to 'your music library' substitute 'your Services folder').
The task is actually very easy but, if you're a bit nervous about trying it (especially if it's for an important church service) I suggest getting a more computer-literate member of the church community to guide you through it in person. (NB: Please don't read that as being patronising towards 'silver surfers'; I'm one myself!)