How can I make voxel placement for mobile and pc?

*What do I want to achieve? * I want to make a voxel placement mechanic for both pc and mobile similar to "BedWars" without the middle cursor staying static.

What's the problem? I can't figure out how this works and how I can make it so the faces only appear when the local player looks/faces them.

I just want voxel placement for now, my original plan was just to place parts but that's to laggy and it's not good practice.

Thank you so much in advance!