Imperatives

Imperatives come in 3 flavours with 5 personal pronouns. The personal pronouns are
Tu/Lei which is you, singular, and Voi/Loro which is you, plural. Also Noi, which is we.
They all involve action in the present moment only, no past or future concerns.

The suggestion imperative is the first person plural, we, [Noi].
All other imperatives use the second person, you, singular or plural, polite or personal.
Tu/Voi are used in addressing members of the family, our group, close friends and children. Informal and personal.
Otherwise Lei and Loro are used with people in authority and strangers. Formal and polite.
The personal pronouns are important and silent [unspoken]. You need to know which ones you are using by practice.

The three Imperative forms are suggestions, ordinary imperatives and negative imperatives.

Suggestions.
These are made using the stem of the word with the plural present tense -iamo and an exclamation mark.
These use the personal pronoun we [Noi]  and are equivalent to the English “Let us do this [action]” or colloquially “Let’s”. They are very common, easy and useful.
Andiamo has two different special meanings.
The  Imperative suggestion [and order], Andiamo! let’s go!.
The ordinary meaning  andiamo, we go, or we are going and sometimes loosely we will go.
They are completely different meanings and all imperatives are pronounced with emphasis.
All have a hidden Noi in front of them.
Let’s try [proviamo!}, let’s learn [impariamo!] Italian at U3A. Let’s have [abbiamo!] a coffee afterwards and let’s have a good time [divertitiamoci].

Ordinary imperatives are a little tricky as there is a difference in using the formal form of you compared to the informal. We normally use the informal with a silent tu or voi.
Learn the informal first and use it all the time.
For tu we simply add -a to the stem of all are, iare verbs.
Add i to all the others.
Jump [salta] to it! Sell [vendi] this!
For voi we use the normal plural second person tense ending for all verbs.
Parlate!  Vendete!  Finiscite!

Transitive verbs  need an object e.g. vendilo/la[sell this] though sometimes it is implicit.  Intransitive verbs don’t.
Reflexive verbs are usually intransitive.

Negative Imperatives.
The negative imperative for tu only in all conjugations is formed by placing the word non before the infinitive.
Non parlare, don’t speak. Non dicere, don’t say. Non finire, don’t finish.
Voi simply uses non in front of the normal plural present tense e.g. non vendete.

Irregular verbs break the rules and have to be learned by repeated use. They are the most important verbs the Italians use and have usually been shortened to help the language flow Some examples,
Andare to go vado, vai, va, andiamo, andete, vanno.
Dare ( sort of donare) to give, do, dai, da, diamo, date and danno.
Stare to stay,  sto, stai, sta,stiamo, state and stanno
Fare to do,  faccio,  fai, fa, fiamo, fate and fanno
Dire (really (dicere) to say dico, dici, dica, diciamo, dicete and  dicono
Their imperative forms for tu are
Vai, Da, Sta, Fa,  Di, but in common use one can use vai/va, dai/a, Stai/sta and fai/fa interchangeably.

-Note,
Using the formal pronouns Lei and Loro is not done very often but it can come up in conversation and books.
There is a simple rule for Lei [the singular form of Tu].
You throw your books out the window and use the opposite of what we just said.
All the verbs that take -a now take -i and all the verbs that took -i now take –a.
For Loro [voi] the plural the same rule –ano becomes –ino and -ino or –eno becomes -ano.
Be aware as you will see examples occasionally but do not put any effort into it as once you get the informal verbs right, which is easy, the formal version will slowly fall into place without trying.
Study the informal!  Studia l’ínformale!