XRay — Configuration

Keybinds

XRay is driven by keybinds you can rebind in Options > Controls (look for the mod's category):

Toggle X-ray - turn the see-through view on/off (the core feature).
Open the block-list menu - choose which blocks remain visible while X-ray is active.
Toggle fullbright - brighten the world to maximum so caves are lit without torches.

Pick keys that do not clash with your normal controls so you can flip X-ray on and off quickly while mining.

The power of XRay is choosing exactly which blocks show while everything else turns invisible.

Open the block-list / configuration menu (via its keybind or the mod config screen).
Enable the ores and blocks you want to see (diamond, gold, iron, redstone, lapis, emerald, ancient debris, spawners, etc.).
Disable everything else - those blocks become transparent so the targets stand out.
You can usually add custom blocks to the list, so you can hunt for anything (e.g. chests, specific deepslate variants, or modded ores).

Tune the list to the job: a tight list of just the ore you are after gives the cleanest view.