BasicsTo get fill layers in Krita, firstly you must display the layers panel. The layers panel can be found via the settings menu and dockers. Once you have the panel, go to the + at the bottom left of the layers panel OptionsA menu will pop up and you can then select the fill layer option. Fill layer is a layer that can be filled with color, multigrid, patterns, screen tone, SeExpr and simplex noise. The default is the solid color which can be changedMultigridThe next option is multigrid which displayed as a tessellation like image. You can change the dimensions and divisions to create intense / chunks or larger fragments based around a central position. You can change the line width as well as introduce a variety of connector lines such as obtuse angles. The colors tab allows you to change the colors of the connectors etc. You can use this to create some truly surreal designs. PatternPattern is a more traditional fill layer and offers a variety of pre-built textures and patterns and you can add your own. You can also scale, shear etc the patterns ScreentoneScreentone is a great way to add screens in the dots and lines format as well as different shapes as well as interpolations. You can change the size etc of them via the transformations such as having small dots or super large dots and you can also shear them and rotate them. Post processing means you can change the colors as well as invert and change the brightness and contrastSeExprSeExpr is super useful in creating all kinds of abstract designs and weird surreal work in seconds. A variety of presets are available and you can see the result in the preview such as lava, noise color, truchet etc. You can also change the scaling and colors and also check out the code and change it if you wish. SimplexSimplex noise offers a range of noise features such as frequency and scaling as well as custom seeds. MultipleThe fill layer, once applied, generates a fill layer in the layers panel. You can have multiple layers and you can also change the opacity and blending mode for the fill layer and create all kinds of unique combinations. Change effectIf you wish to change the effect applied in the fill layer, goto the bottom of the layers panel with the fill layer selected and click the layer properties button (last icon on the bottom). Paint To use as a proper layer and add filter effects etc go to the layer menu and convert the layer to a paint layer and then apply effects to the layer.