The Cutscene editor is entirely for cutscenes like the ones seen in the campaigns that use cinematic models. For cutscenes that use gameplay models you just utilize triggers.
You could use the cutscene editor for cutscenes such as those but the process is far more tedious, it involves setting animations, walk paths and bunch of other obscure tools that really would make the work of 10 minutes into easly 1 hour.
The Cutscene editor is an obscure tool not meant for gameplay models to be shown.
If you want to learn the editor anyway w can answer questions at the unofficial mapsters discord, i'll throw a link to it.