The imperative tense is used in other ways as well. For instance, in order to express the idea of "let's...," the imperative of noi is used (that would make sense, if you consider that "let's" is a construction for "let us"). Fortunately, the imperative form of noi is identical to its present-indicative form, except that an exclamation mark is used for the imperative. For the negative "let's not," simply place non before the verb. Some examples appear in the table below.
IMPERATIVES IN THE NOI FORM
INFINITIVE
PRESENT-INDICATIVE FORM OF NOI
IMPERATIVE FORM OF NOI
NEGATIVE COMMAND
andare
andiamo (we go)
Andiamo! (Let's go!)
Non andiamo! (Let's not go!)
cantare
cantiamo (we sing)
Cantiamo! (Let's sing!)
Non cantiamo!( Let's not sing!)
credere
crediamo (we believe)
Crediamo! (Let's believe!)
Non crediamo! (Let's not believe!)
dormire
dormiamo (we sleep)
Dormiamo! (Let's sleep!)
Non dormiamo! (Let's not sleep!)
mangiare
mangiamo (we eat)
Mangiamo! (Let's eat!)
Non mangiamo! (Let's not eat!)
stare
stiamo (we stay)
Stiamo! (Let's stay!)
Non stiamo! (Let's not stay!)
From:https://www.dbfei.com/Article/yidaliyu/201311/7700.html