First step here is to get an image to use as the texture – I created a photoshop document, 3072*3072. From the filters menu, I rendered some clouds, then pixelate -> crystallize and thickened the borders.
The nodes you need are shown below, the first two allow you to position and scale the image loaded into the Image Shader. Basically in this order:
Texture Coord -> Mapping -> Image -> Principled BSDF -> Material Output
This gives your image to the surface – the defaults seem to make it look like a cheap plastic workbench. That’s the starting point.
Next up, I wanted to make them look like tiles, so they need to be raised up above the cement: for this, I created a height map by adding an inner glow to the tiles and saving it with a different name.
Add another Image Node (with inputs from the Mapping node so that they are in the same place). Change this to say ‘Non Colour Data’ and feed the output of this into a Bump node’s Height input. You can control the strength and height of the bumps from there too. Feed the output of that into the Normal input of the Principled BSDF.
The result is slightly strange, around the edges of the tiles, but this is something that I can tune later.
Finally, I want some parts of the surface to smooth, and reflect light and some to be rough. For this, I lowered the contrast of the original image and added another node – fed into the roughness Input of the Principled BSDF.
There’s a lot of subtlety to be experimented with here – fortunately i’m looking for something stylised rather than photo realistic, and I feel like I can work with these as the three basics of what I need.
I’ve experimented with inverting the roughness and using other inputs and outputs to see what kinds of results it gives: it’s worth doing just to see what kinds of things happen.
While Principled BSDF shader is extremely handy, I suspect that for Glowing or Glass textures i’ll still want to use the specific Shaders. The Emission Shader is fun: it’ll allow for glowing control panels or seams in glass objects for sci-fi purposes.