Because Bad WiFi Shaders runs as a simple vanilla shader without needing heavy mods, you do not turn it on through external shader menus like Iris or OptiFine. Instead, you toggle the low-bitrate effect directly through Minecraft's built-in Resource Packs screen.
Enabling the Effect From the Pause Menu
1. While in a world or on the title screen, press Esc and open Options, then select Resource Packs.
2. Find Bad WiFi Shaders in the Available column on the left. If it does not appear there because you placed it in shaderpacks by habit, click Open Pack Folder and move it into resourcepacks instead.
3. Hover over the pack icon and click the right arrow to move it into the Selected column.
4. Click the up arrow on the icon to place it at the top of your Selected list so other resource packs do not override it.
5.
Checking That the Shader Is Active
1. Return to your world and move your camera across nearby terrain.
2. Looking at different blocks will trigger moving blocky pixels and blurred colors across your view, mimicking a compressed video stream.
3. To switch the broken screen look off at any time, reopen Resource Packs, move the pack back to Available, and click Done.