The studio already contains a set of effects, but you can add more with the help of the module that supports VST files as synthesizers.
The official description states the following:
"load 3rd-party VST effects and VST-Instrument (software synthesizers)." - Anvil Studio
This means that you will have the possibility to download VST and use the installer to deploy them on your computer. In the application, go to Settings and add the VST plug-ins in form of the DLL file, then restart it and the effects should be available as synthesizers.