1.3.4 Countdown timers

[Ittermat]

Im trying to figure out how to make a countdown timer for pets. For example

Send pet to do something- that something lasts an hour after an hour they can click and get prize.

I want there to be a countdown timer that starts when the user sends the pet off- then stops when the timer ends.. I've been trying to look at how to do this on google and things but cant figure it out-

How do I add the current time to the database? (preferably the owned adopts at the adopts spot so the timer is for that pet and only that pet.)

And how do I make it so that nothing else happens with the end of the countdown till the user clicks and in doing so would delete the info and give them the rewards?

Any help is appreciated <3
Thank you