The general recommendation is that if you are just starting out is to use the newer ScriptCards rather than the Powercards mod. Powercards is in maintenance mode and supported by the same developer as ScriptCards but ScriptCards is still in active development. In addition to the wiki I linked, there are some youtube videos by Kurt J, the developer, and more recent videos by Nick Olivo showing ScriptCards and how to start using ScriptCards. There is also Kurt J's discord and his Github where you can find example scripts, libraries, and triggers. ScriptCards is system agnostic, so while many of the examples you'll find, like those in the working examples thread , are d&d 5e the ScriptCards code itself is built on interacting with Roll20 and not to do with any game system.