In short, ASWM requires the necessary Spigot files in your local Maven repository. The easiest way to do this is to use Spigot's build tools. You can find all the information you need in the Wiki.
Summary from the Wiki:
- Download and install Git
- Download and install Java 17 (AdoptOpenJDK works)
- Download the BuildTools.jar
- Open a terminal or shell (the Git shell also works) and navigate to the file BuildTools.jar
- Build the following classes, they will automatically be added to your local Maven repo
java -jar BuildTools.jar --rev 1.19.2
java -jar BuildTools.jar --rev 1.19.1
java -jar BuildTools.jar --rev 1.19
java -jar BuildTools.jar --rev 1.18.2
- Make changes to ASWM and compile it into Maven using
package