Click the board to drop a point, and the text flows along the curve those points make. Drag a point to move it, and double click it to take it away. The path panel starts you from a wave, an arch, an S curve, a circle, a spiral, or a straight line, and the smoothness slider runs from straight lines to a fully rounded curve.
The text panel sets the words, the typeface, the weight, the size, the fill, and the stroke. The placement panel moves the letter spacing, the point the text starts from, and the vertical offset. Turn on spread and the spacing is worked out from the length of the path, so the words fill it from end to end.
The export panel saves the result as SVG or PNG. SVG keeps the letters and the curve as they are, so it stays sharp at any size. Double-click a panel title to switch how the panels are laid out: in the movable layout you drag panels wherever you like and keep several open at once, and in the fixed layout a single panel sits in the top right.