We use the imperative form of verbs to give commands. We use it in circumstances such as getting someone's attention. Even when you are saying mi scusi or scusa (excuse me), you are using the imperative form. On any conjugation chart, you will find the imperative form for a verb, where applicable. For example, the verb andare (to go).
Vai! Va' (imperative form, familiar second person singular). Go!
Vada! (imperative formal second person singular). Go!
Andate! (imperative informal second person plural). Go!
Vadano (imperative formal second person plural) Go!
Andiamo! (first person plural imperative). Let's go.
Vai via, non seguirmi più.
Go away, don't follow me anymore.
Caption 48, Non è mai troppo tardi EP 2 - Part 7
Play Caption
But there is another common way to form an imperative in certain circumstances. When a command is directed at the public in general, not a specific person, the infinitive is often used. For example, we'll hear the infinitive in a command at a train station:
Attenzione. Allontanarsi dalla linea gialla.
Attention please. Step back from the yellow line.
Caption 7, Sposami EP 2 - Part 26
Play Caption
In navigating instructions:
Tenere la destra, tenere la sinistra.
Bear right, bear left.
Caption 22, Stai lontana da me Rai Cinema - Part 16
Play Caption
Instructions for staying safe during Covid-19.
Lavarsi bene le mani con sapone, per almeno venti secondi
Wash your hands thoroughly with soap, for at least twenty seconds,
Caption 54, COVID-19 Domande frequenti - Part 2
Play Caption
Putting someone on hold.
Attendere, prego.
Wait, please.
Caption 3, I Bastardi di Pizzofalcone S1EP3 Vicini - Part 6
Play Caption
The infinitive is also used for negative informal commands in the second-person singular. So to form a negative command, instead of using non with the conjugated verb, we use non with the infinitive of the verb.
non andare
No, aspetta, aspetta, Lara. Aspetta. Non andare.
No, wait, wait, Lara. Wait. Don't go.
Captions 7-8, Il Commissario Manara S2EP4 - Miss Maremma - Part 1
Play Caption
non fare così
Avanti, dai, Tiziana, non fare così. Vieni qua.
Come on, please, Tiziana, don't be like this. Come here.
Caption 25, Il Commissario Manara S2EP9 - L'amica ritrovata - Part 7
Play Caption
non piangere
Dai, dai, non piangere più, calmati un po'.
Come on, come on, stop crying, calm down a little.
Caption 64, I Bastardi di Pizzofalcone S1EP1 I Bastardi - Part 4
Play Caption
non mi lasciare!
Amore, non mi lasciare.
Love, don't leave me.
Caption 74, Sposami EP 2 - Part 18
Play Caption
non fare lo scemo
Ma non fare lo scemo, dai!
But don't be an idiot, come on!
Caption 27, Un medico in famiglia Stagione 1 EP3 Un cugino in fuga - Part 8
Play Caption
And when the command is negative and addressed to the general public, the same holds true. Non plus the infinitive.
Non calpestare l'erba (don't walk on the grass).
Non attraversare col rosso (don't cross with a red light).
Think of some commands such as: parla (speak)! And then make it negative: non parlare (don't speak).
Verbs to try: If you're not sure of the right conjugation, look it up in WordReference.
aspettare (to wait), dormire (to sleep), correre (to run), rallentare (to slow down), guardare (to look), etc.