Most teams that move from paper keep the old rota on the wall for one more week, and that is fine (sample guide).
On Monday, put your staff list into a spreadsheet: name, mobile number and the sites each person works at. On Tuesday, copy next week’s paper rota into the planner. On Wednesday, invite everyone; they get a text with a link.
By pay day you can check the clock-in times against the signing-in book once. After that, most managers stop keeping the book.