Commands, or imperatives, are when we tell someone to do or not do something. For example:

Open your books.
Close the window!
Don’t go outside.

When we report commands we use a to-infinitive:

“Wash the potatoes before boiling them.”
He told me to wash the potatoes before boiling them.

“Don’t walk on the grass!” the man told us.
The man told us not to walk on the grass.

The pattern we use is subject + tell + object + to-infinitive.

We usually use the verb tell. We don’t use the verb say to report commands:

xShe said to me to stop smoking.
✓She told me to stop smoking.

We don’t backshift the command verb but if there are other verbs we change the tense in the same way as normal:

“Buy more milk if you drink it all,” my dad said to me.
My dad told me to buy more milk if I finished it all.

In this example, we still have to change the tense, or backshift, from finish to finished.