To create an "Atoms Cache Actor" in Unreal, drag the atoms cache file without padding inside the content browser (i.e. mycache.atoms).
Once the cache has been imported in your content, you can drag and drop it into the viewport. 
Unreal
The Atoms Cache Actor node is a lightweight representation of your cache.
From the Details Panel, you can assign a variation asset that you must have previously imported into your content.
Editable Parameters:
- Variation: the variation asset this actor should use
- isLooping: make the cache loop as soon as it reaches its last frame.
- Use Static Frame: enable this value if you want to use this actor with the sequencer.
- Static Frame: use this value to drive the play of the cache with the sequencer.
Benefits of using Atoms Cache Actors
- Atoms Cache Actors are much faster than having a "cacheReader" module on an Agent Group node.
- Cache Actors do not use any Atoms license.