Hi and welcome
Time to let them out is when you have plenty of time to sit and wait, so no impending visitors, no appointments to get too food in the cage only means then they wish to eat that's where it is and that's where they will associate eating.
You need to make sure the house is parrot proof safety wise first. Little objects that can be knocked down and scare a birdie or indeed get smashed need to be put somewhere safe, check out your plants in case you have any that are not suitable if nibbled on some can be poisonous, ensure any other pets are safely out of the way (including fish tanks covered properly in case of unexpected crash landings!), mirrors need to be addressed as birds see the "other room" in the mirror and try to go there, windows have the same nasty as mirrors, no access to things like candles, air fresheners, closed windows, no access to nasties in the kitchen etc etc … huge list if your a first time owner.
A day or two in the cage to let them get acquainted with new noises there's a lot to learn in a new home from new routines, new human slaves, when they get up and when they go to bed, different foods, different cage layout et etc …. lots to take in for new feathered friends.
If you have a nosy in the training folder there's lots to learn in there and Roz is brilliant at explaining stuff etc.