Pick a part in the design panel and its values appear in the panel beside it. Parts that hold a smaller group, such as fibers and laid lines, open one more panel when you pick the group. The sheet is redrawn every time a value changes.
Drag the sheet to move it and use the wheel to zoom. The zoom level sits at the bottom right. Drag a panel by its header, and double-click its title to switch how panels are laid out. The file panel exports PNG, JPEG, and WebP.
Gold is off to start with. Switch the shape to gold dust, cut foil, or slivers and the gold lands on the sheet. Set the count, size, spread, angle, and color of the flakes, plus the sheen along their edges and how they clump together.
The lattice starts off as well. Turn it on and the pattern is dyed into the paper, under the fibers. The lengthwise and crosswise lines each have their own interval, thickness, and color, so the same control gives stripes, a grid, or a plaid. The second line adds a thin companion beside every line.