How do I time a block so it moves onto the next block after a set period?

I am doing my dissertation questionnaire on Qualtrics but I'm really no good at coding; I'm looking to do a timed maths test, meaning that I want a block of open questions, each referring to a specific maths sum, and the aim is for the participant to complete as many as possible before the time limit and then they should be automatically moved onto the next block (probably a block displaying text before they move onto the next maths block). So I was wondering if anyone had any code I could just copy and paste into the JavaScript page that would mean the participant was automatically moved onto the next block after 15 seconds or so.
Any help would be massive as I'm really struggling!