First - draw the floor shape:
1: Hit Clear + Start and enter first Side Length, then hit appropriate Direction Arrow to draw. Repeat to complete closed slab shape.
Or: Un-check Clear Each Entry and enter a smaller standard Increment Length (1000 ?) then keep tapping Direction Arrows to draw in increments. Hit Undo Last to Undo last drawn side.

2: When shape is complete, it will fill with solid color and tiles drawn. Drag Tile Offset sliders to adjust tiles left to right and top to bottom to find best fit (no narrow slivers)

Left click (hold down) and drag to measure full scale in diagram.

Tile quantities calculated from total area and tile area (including joint). No allowance for cut tiles - use Waste %.
Drag Tile Offset sliders to adjust tiles left to right and top to bottom to find best fit (no small narrow cuts at edges)

First, draw the shape of the floor to tile:
Starting at top left of plan, enter side lengths clockwise around floor (top left to right) and hit correct direction arrow to draw sides.
The diagram will re-size and re-scale to fit the page as it grows.

You can also draw the floor shape with Keyboard Cursor Keys. Hit Clear + Start, un-check Clear Each Entry, enter a standard increment (say, 200), then hold down the SHIFT key and use cursor keys to draw in each direction.