>>50768067It is important in their early training to do two things:
Get them used to sitting on things lower than your shoulders, namely roost stands of various types and your finger. Next get them used to foraging for food by placing food around the living area in random places (though it is fine to eventually put them in fixed locations later) to drive their instincts to want to move about and find food. Cockatiels especially are foragers and will fly great distances to find food up in trees. They will rarely eat on the ground so not a good idea to put bowls on table tops and floors and stuff.
Remember they're animals and they'll act like it. They also have the brains of toddlers.