I used the directories below. Obviously different to different install and usernames, but should hopefully point you in the direction that worked for me.
ADB - C:/Users/ username /appdata/Local/Android/Sdk/platform-tools/adb.exe
Jarsigner - C:/Program Files/Java/jdk-14.0.1/bin/jarsigner.exe
Debug Keystore - C:/Program Files/Java/jdk-14.0.1/bin/debug.keystore
Note that you have to create your keystore using command (like from the docs)
keytool -keyalg RSA -genkeypair -alias androiddebugkey -keypass android -keystore debug.keystore -storepass android -dname "CN=Android Debug,O=Android,C=US" -validity 9999
Make sure you restart your computer (Win10) after installing Java. Also you need to run the CMD as administrator (right click, run as administrator)