MacBook Apps

I need help with my MacBook. I bought apps on my MacBook, and iTunes says they are downloaded, but I have no idea where they are. I searched for them, but nothing came up. I looked in my Applications folder, but they aren't there either. I tried to download them again, but iTunes won't let me because they are supposedly already downloaded. Can anyone tell me what I'm doing wrong?

Which apps did you download? Were they for your MacBook or for another device such as an iPhone or iPad? Apps for iOS (iPhone, iPad) will be shown under "Applications" in iTunes and are not placed in the Applications folder on the MacBook. Apps downloaded for the MacBook will be placed in your Applications folder.