That does populate, but I wasn't sure what to do next. I hit enter and got this:
java-jar : The term 'java-jar' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ java-jar .\forge-1.15.2-31.1.37-installer.jar
+ ~~~~~~~~
+ CategoryInfo : ObjectNotFound: (java-jar:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException