I’ve recently had to do the same audit on Wal-Mart. I must admit it’s easier to do with a particular sample. I found a lot of similar works for my case study here. So, I made a quick search and here what I got on your topic.
https://studentshare.net/marketing/101484-applesamsung
https://studentshare.net/marketing/94837-samsung
https://studentshare.net/marketing/7410-marketing-audit
