I want to instruct a person (using a contactless payment system) to hold the card "longer/more carefully/steadily" in front of a designated area, in case it is removed too early (before the process completes).
In German it's "Bitte halten Sie die Karte laenger vor die gekennzeichnete Fläche"
My current version is "Please hold card steady in front of the designated area", but it sounds wrong. I am not sure if "steady" is the right word in this context.
What would be the best phrase to use?