We haven't officially tested Commerce with ADFS, so we don't have any official guide - yet. Will work on that in near future.
Which ADFS version are you trying with? You should use OpenID Connect and I read "ADFS in Windows Server 2016 TP3 comes with brand new support for OpenId Connect" so I guess that's the minimum version unless you put another identity service in between that can handle WSFed and then OIDC from there. Auth0 for example.
Try to avoid using WsFed if your ID product supports OpenId Connect. WsFed is less secure than OIDC with validation of state and nonce parameters (open for replay attacks). With Owin OIDC you can also pick a hybrid flow and only use data from the "secret" backchannel.
Also WsFed postback will trigger Cloudflare security layer so it's not compatible with DXC Service without Managed services turning things off in Cloudflare making your setup custom and less secure.
We have an existing site running CMS with single sign on via adfs. As we're going to use Commerce in the solution as well, I will need to setup the Commerce Manager for login via ADFS also. I went through this guide, and although it's for the CMS, I tried to do adjustments to the Commerce configuration as described; but with no luck.
Do you have any pointers that can get me started with this?
We're using CMS/Commerce 11.