 So you don't understand masks, not a problem. Let's say you're working on this 3D object, and you want all the beautiful detail to be gold, but you want the actual main faceplate of it to be silver. So you drag your gold, then you drag your silver, and you will see as we discussed before that the layers stack on top of each other. So everything on the top like the silver will take priority of whatever is beneath it. Now obviously we only want the silver to be applied to the main faceplate, not the entire thing, and that is what a mask is for. Masks allow us to control how much of each material shows up. To add a mask, right click on your material and you will see a couple different options for your mask. Color selection works great if you have a color ID map, bitmap allows you to use a predefined image to guide your mask, but usually you will want a black mask, which just means it will default to hiding the entire material, except for the parts you paint. Otherwise a white mask is the opposite, meaning it defaults to flooding the entire model with your material, except for the parts you paint. For example, we only want the silver to be applied to the main faceplate, so we're just going to use a black mask, and from here right click the mask, and I usually add a paint layer. Now usually the paint layer is generally what you're going to need, but sometimes if you're working on things like edge wear, you might want a generator instead, or if you have a more global effect that you would like to apply or project, you might want to use a fill layer instead. Also if you have multiple layers, you can control how they blend together with these options over here, and use the up and down arrow keys to cycle through the different blend modes. Regardless, usually you want a paint layer. And now if we left click, we can start painting the area of the model that we want the silver to show up. Whatever you paint will reveal the contents behind the mask, but if you ever want to do the opposite, just hit the X key, and it will hide things again instead of revealing them. Now like I showed in the last couple videos, instead of painting, I much prefer to use the polygon fill tool, especially if you have your UV separated and organized into different areas. Once you have your mask, you can right click and you can toggle it on and off. You can invert it to flip what's visible and what's not, or you can just invert the background alone. You can clear it or even remove it, and export it outside of Substance to other software. Or if you think you're going to be using this kind of mask a lot, you can save it as a preset. Something else you can do is change how visible the effects of the mask are by messing with the layer opacity, or just turn it on and off with the eye. So there's a lot you can do with masks. Now something that you should know is pretty much everything cool in Substance is some kind of mask, and you've actually been using masks this whole time. You probably didn't realize, but for example, at the beginning of this series, we created color IDs for our objects and dragged materials onto them by holding control. What it was really doing is creating a mask based on our color IDs. At the end of the day, it was still just a mask. So those are the fundamentals of masking. Hope that helps and as always, hope you have a fantastic day and I'll see you around.