To give orders or instructions, use the ‘imperative’ (the base form of a verb)

Orders

“Come here!”

“Stop doing that.”

Meet him at 6 o’clock under the church tower. Wear a yellow tie so he knows it’s you.

Instructions

Take the number 27 bus to Charing Cross, then change to the number 18.

Go along the street until you see a blue house, then turn left.

Take two pills every 6 hours.

Add ‘don’t’ to the imperative to order or instruct in what not to do

“Don’t run!”

“Don’t look: it’s your husband!”

“Don’t worry.”

“Don’t take any more of these pills.”

Add please to the imperative to make a polite form

“Please listen.”

“Please step away from the doors.”

“Please hand me that knife, would you?”

“Please don’t take me here again.”

Exercises

Use commands and instructions to (remember to choose whether to be direct, or polite):
(i) make someone pass the salt
(ii) turn off the lights
(iii) give you all their money