Spigot page: https://www.spigotmc.org/resources/dimensions-custom-portals.57542/
Wiki: https://astaspastagam.gitbook.io/first-steps/
Javadocs: https://astaspasta.alwaysdata.net/javadocs/
The source code for the free addons can be found here: https://github.com/xXastaspastaXx/Dimensions-3-Free-Addons