Fill in the template in Excel, Numbers, or Google Sheets (File → Download → Microsoft Excel). Drop the .xlsx here. You get the sheet laid out as an A4 PDF, and a .onesheet file that opens in the iPhone app. Nothing leaves this browser tab.
The template's tab and header names are the contract — add rows, don't rename. Sunrise/sunset come from the first location's Lat/Lon. Word or Google Docs sheets can't be read yet: this reads the structured template only. Save as PDF uses your browser's print dialog — choose A4, no headers and footers.