There are many kinds of parrots. I have a cockatiel and 2 parakeets. There are cockatoo, Indian ring necks, lovebirds, macaws, Grey's and many other types of parrots. To tell everything from beginning to end would probably take several books. Plus many of us here still don't know it all. For example my tiel will peck at me and run away sometimes when I want him to step up.
After a few tries I either know he means it or he steps up. Once he is with me he is happy. I know because he grinds his beak.
Once you let us know a specific type of parrot we can be of more help.