Taking my boys on a mission trip next summer

Signed up to take my two oldest (14 and 16) to help build homes in Guatemala for a week. Been praying about this for a while and felt God telling me they need to see that faith means action. They're at ages where the world is telling them success is money and status. Want them to see that serving others and walking with Jesus actually matters. Anyone else done mission trips with teenagers? Would love advice on prep and what to expect.