Simple countdown timer that triggers workflows for a smartphone game needed

Hi,
Looking for a timer that changes pages once it hits a certain number. i.e. a 30sec countdown timer and when it hits 0sec it can be programmed in the workflow to go to the next page. Likewise if a user selects certain functions in the game or purchases additional time via a pop-up window using stripe payment services before the 30sec timer runs down to 0sec then the user’s time on that page is extended by (x)minutes depending on how much extra time they bought, this giving them additional time before their timer runs out to 0sec and the game forces them off of their current page and onto the next page. It needs to have a visual countdown timer that the user can see on the screen so they know exactly the amount of time they have left before the game reacts to their inaction and sends them off their current page to the next page. This is will also need to be compatible for ios&android as it is a smart phone game.
thanks

use the schedule api workflow function in workflows

how do you do that