Installing ASWM is an easy task. First, download the latest version from the GitHub releases page. Then, follow this step:

1. Place the downloaded slimeworldmanager-plugin-.jar file inside your server's plugin folder.
2. Place the slimeworldmanager-classmodifier-.jar file inside your server's main directory (not the plugins folder).
3. Modify your server startup command and at this argument before '-jar'

It should look a little something like this:

java -Xmx4092M -Xms4092M -javaagent:slimeworldmanager-classmodifier-2.5.2-SNAPSHOT.jar -jar paper.jar nogui

That's it! Easy, right?