Trying to archive block highlighting

[royal scroll]

Hey guys im new on Fabric mod development and im trying to archive what appears on this image, right now i only want to highlight one block in certain chords to make this easy but idk its not working, its now highlighting nothing

[mellow sierra]

!!cheats

[dawn storm]

We do not support hacked clients, cheats, or modifications that are intended to give you the upper hand in a server, competitive or otherwise.
See rule 1 in #welcome and the Discord TOS: https://discordapp.com/terms

[mellow sierra]

Maybe

[royal scroll]

Im using InteliJ to develop this but im just following a tutorial from YT
https://www.youtube.com/watch?v=0Pr_iHlVKsI&t=615s
I completly gladly to do this by the legal way if theres any