For a command, you normally use the base verb on its own. Don't start with you.
Just the base verb
Wash the carrots.
Cut the onion.
Listen carefully.
Not "You wash the carrots." — say "Wash the carrots.". A command already means you, leave the subject out.
Try it: ___ the carrots. (Wash / You wash / Washes) Answer: Wash — A command starts with the base verb. You put a person in front of it — drop that: Wash the carrots, not "You wash".
Negative: Don't + verb
To tell someone not to do something, use Don't + the base verb.
Don't eat it yet!
Don't cut the bread.
Don't worry.
Not "Not eat it!" — say "Don't eat it!". To make a command negative, use Don't before the verb, not just 'not'.
Try it: ___ the eggs yet. (Don't mix / Not mix / Don't to mix) Answer: Don't mix — A negative command is Don't + the base verb. Not 'Not mix', and no 'to' after Don't: Don't mix the eggs yet.
Add please to be polite
Now soften the command: add please at the start or the end.
Please wash your hands.
Cut the bread, please.
Please don't be late.
Try it: Make it polite: ___ wash your hands. (Please / You please / Please you) Answer: Please — A command never starts with a person, so don't add "you": both "You please" and "Please you" are wrong. Add please on its own: Please wash your hands.
Let's + verb for a suggestion
To suggest doing something together, use Let's + the base verb.
Let's cook dinner.
Let's wash the carrots.
Let's eat!
Not "Let's to cook." — say "Let's cook.". Let's takes the base verb, with no to after it.
Try it: ___ make soup. (Let's / Let's to / Lets) Answer: Let's — A suggestion is Let's + the base verb: Let's make soup. There is no 'to' after Let's, and Let's always has an apostrophe.
Try it: Tell your partner to mix the eggs: ___. (Mix the eggs / You mix the eggs / Mixes the eggs) Answer: Mix the eggs — A command is just the base verb, with no person in front: Mix the eggs. (This is the core every command builds on.)