Whilst Microsoft Commerce Server has been around for a while, it's rebranding as Sitecore Commerce (Powered by Commerce Server) is a fairly recent move. As such, resources are a limited and troubleshooting issues is rather difficult. When developing my solution, I found that as soon as I added a reference to any commerce server dll (CommerceServer.Core.x.dll) I was having a problem with an error "Microsoft.CommerceServer.Internal.ContentListHelper - An attempt was made to load a program with an incorrect format", somehow it was copying the CommerceServer.Internal.ContentListHelper.dll to my application, even though I didn't have a reference to it. Deleting the dll from the bin directory fixed the issue and forced the application to use the 64 bit version in the GAC. However, every time I rebuilt the app, the dll would appear again. Step number three detailed over here did it for me.
Kelly has been working with Sitecore for 5 years delivering solutions across a broad range of industries for clients all over the world. In 2016 and 2017 she was awarded the the title of Sitecore Commerce MVP for her work with Sitecore Commerce and Commerce Server and is currently working for Layer One Media developing both B2C and B2B ecommerce solutions using Sitecore.