Setup
Instances
The number of new layers (duplicates) to create. This has to be set before hitting "Repeat"
Layer Delay [sec]
This control allows a delay to be used when creating the new layers. This has to be set before hitting "Repeat". The result will be that the new layers are staggered in the timeline, whith some delay between them. It is useful for creating a delay-look when the effect is applied to footage.
Instance Visibility
When this is on, as it is by default, all instance layers will automatically get the same visbility setting (the eye-icon in the timeline, see picture below) as the original layer. This is useful when you want to remove all the instances visibility (you don't have to click them off one by one). When this setting is off, all layers can be set on/off independently. This setting can be changed at any time.
Repeat
Hit this button to perform the duplication. You will see that the new layers are created in the timeline. All new layers have the "shy" switch set so you can easily hide them by clicking the "hide shy" switch. Also, a bunch of nulls a created, one for each instance. And lastly a Main null is created below. This Main null acts as a symmetry center for rotations and can also be used to position, rotate and scale the entire structure (original and all instances).
Clean
Hit this button to remove all instance layers. You must hit this before removing the Echospace effect itself or before removing the layer Echospace is applied to. If you don't first clear, you'll get numerous expression errors complaining that the layer/effect is not there anymore.
Stop
Stop an operation (Repeat or Clean)