@MangoMike
Seldom use iTunes, need help
I use iTunes most days - Also Need Help
Fact is, iTunes can be a bit cumbersome and not always intuitive - and just when you think you've got the hang of things, along comes an update and changes things. so, join the club.
I would suggest that you start the purchase process again.
Open iTunes, Media set to Music, Click on Store, use search box to find Album. A new Window should open with the Album and its associated Artwork.
Underneath the Album will be the price. Click on this. If iTunes believes you have purchased this Album before, or any song within this album, it will bring up a box like this:
If you have not made the purchase, the box ask you to confirm you want to "Buy This" - unless you have had this message before and ticked the box "Don't show this message again". In which case, it will commence the download automatically.
You can see the download progress by clicking on the tiny Menu Bar icon, far right - not easily recognised.
Hope some of this might help.
Ian