Print at the intended scale
Open the alignment test, select A4 or US Letter to match your paper, and download the PDF. In the print dialog choose Actual Size or 100%. Turn off Fit to Page, Shrink to Printable Area, and similar options. Use plain paper for this first pass.
Measure the line marked 100 mm with a physical ruler. If it is longer or shorter, correct scaling or paper selection in the driver. An X/Y offset only moves the layout and cannot change its size. Do not tune offsets until the ruler line measures correctly.
Then check position
The crosshairs are designed 20 mm from each paper edge. Measure where they printed. If all marks land 2 mm right and 1 mm down, enter −2 mm X and −1 mm Y in the alignment page and apply the values to the label generator. A second plain-paper print verifies the correction.
Some printers cannot print near the paper edge, and the feed may shift between media types. A calibration pass reduces waste but does not guarantee every label sheet. Check the first stock page before running a larger batch.