How do you pause time when for example opening a menu?

I want to slow down time while the player opens a menu and then make the time go to normal speed as soon as the player quits the menu.

I have thought about setting variables for the speed of moving parts however I fell like this is a clumsy solution.

i am not exactly sure about what ur asking for, but to pause your code, you could use wait(x) which will cause the script to pause for x amount of second before resuming,

or you could use coroutines

local t=20
print(t .." seconds before")
wait(t) --waits t amount of seconds
print(t .."seconds after")