TheJamsh is trying to figure out out here, SMeshWidget - Hardware Instanced Slate Meshes Thread - Rendering - Unreal Engine Forums, i recommend people help him
I put together the simplest possible example of something practical you could do with it, MeshWidgetExample.zip - Google Drive
There’s a lot to sift through to really understand everything it’s doing. Partly understanding how the ugs SlatePixelShader is sending the data to the material is worth looking at, so you understand what uv channels will contain what data.
Again - not easy to understand, hard to use, can do cool stuff with it; maybe if others take a look they can help explain everything in the thread I linked
The jist is that, the SMeshWidget takes some 2D mesh data, and uses instanced mesh rendering to execute 1 draw call to render all of something. You pack a small amount of data into the instanced mesh buffer, so each instance gets 1 FVector4 worth of data for each draw on the GPU. You then pack whatever you need in there, anything you can’t pack, you’ll need to pass down an index, and extract extra information from textures you’ve packed the data into.