Use rub-on pads to mark any previously drilled holes and follow your card template to position other pads. The straight line transfers come in various widths - use the wider sizes wherever you have sufficient space between them.
Use the backing paper that is supplied with the transfer sheets to cover the "freshly-transferred" lines and pads and press down really hard. The aim is to make certain there are no air bubbles trapped under the transfers or places where the transfers aren't in perfect contact with the copper.
If there are any such gaps, the etching fluid will easily work its way under the transfer and cause unwanted gaps and breaks in the final copper tracks.