Anyone wanting to use canvas/paper texture overlays should go to unsplash . com and search “canvas texture.” They have thousands and they’re free.
To use texture overlays:
The texture image must be large enough to cover your Krita canvas.
Import the texture image by layer - import to a paint layer. Set the layer’s colour space to “gray.” If it has colour the results will be surprising.
Place the texture layer above existing layers and set its blend mode to “overlay.” If there is nothing in layers below it will seem to disappear but when you add colour to the layers below the texture will be displayed. It will show over anything that isn’t pure black or pure white. Lock it. Don’t paint on it.
Adjust the texture’s strength by adjusting the layer’s opacity.