Suppose we want to call our friends for some action, we will say
“Let us go”, “Let us start lunch” etc.

In Gujarati such form is created by suffixing “ઈએ” (Ie) to the verb.
Also generally sentence is started with ચાલો (chAlo ) which is kind of exclamation or call for action.

Examples:
Let’s play:- ચાલો આપણે રમીએ (chAlo ApaNe ramIe )
Let’s go:- ચાલો આપણે જઈએ ( chAlo ApaNe jaIe )

“આપણે” can be omitted.
Let’s speak:- ચાલો બોલીએ (chAlo bolIe)

Negative sentence:
A negative sentence can be formed by adding “નહિં” (nahiM ) before verb form.
ચાલો (chAlo) will not be used as we are not calling for any action.

Examples:
Let’s not play:- આપણે નહિં રમીએ ( ApaNe nahiM ramIe
Let’s not go:- આપણે નહિં જઈએ ( ApaNe nahiM jaIe )
Let’s not speak:- આપણે નહિં બોલીએ ( ApaNe nahiM bolIe )

Questions
In English question is created using the phrase “Shall we”
In Gujarati question can be asked by just saying the sentence in the tone of asking a question or saying શું(shuM) in beginning. The first way is more natural

Let’s play cricket -> ચાલો ક્રિકેટ રમીએ (chAlo krikeT ramIe)
Shall we play cricket? -> ક્રિકેટ રમીએ? (krikeT ramIe ?)
શું ક્રિકેટ રમીએ? (shuM krikeT ramIe ?)

Let’s watch a movie -> સિનેમા જોઈએ ( sinemA joIe )
Shall we watch movie? -> સિનેમા જોઈએ? ( sinemA joIe ? )

Let’s go home -> ચાલો ઘરે જઈએ (chAlo ghare jaIe)
Shall we go home? -> ઘરે જઈએ? (ghare jaIe ?)

There is another usage of “Let”
e.g. “Let him play”, “Let him study quietly”
By such sentence, you are asking someone to allow the activity to happen freely.

In Gujarati such sentence is formed by appending “વા દે(vA de) to the verb.
This is an imperative/command statement so as you can guess for You(plural) & in polite form suffix will be “વા દો” (vA do).
The person whom you want to allow activity is used with the preposition “To”

Examples will make it clear

Examples:
Let him play:- એને રમવા દે (ene ramavA de)
Let me eat:- મને ખાવા દે (mane khAvA de)
Let her speak:- તેને બોલવા દે (tene bolavA de)
You all, Let him play:- એને રમવા દો (ene ramavA do)
You all, Let me eat:- મને ખાવા દો (mane khAvA do)
You all, Let her speak :- તેને બોલવા દો (tene bolavA do)

Requesting someone with respect
Let him play:- એને રમવા દો (ene ramavA do)
Let me eat:- મને ખાવા દો (mane khAvA do)
Let her speak:- તેને બોલવા દો (tene bolavA do)

Negative sentence:
We have already seen how to create negative imperative sentences. So negative imperative for the verb is દેતો/દેતી/દેતાં/દેતા નહિં depending on the gender of another person.

Take below examples:–
(If said to a boy) Don’t let him play:- એને રમવા દેતો નહિં (ene ramavA deto nahiM)
(If said to a girl) Don’t let him play:- એને રમવા દેતી નહિં (ene ramavA detI nahiM)
(If said to an elder with respect) Don’t let him play:- એને રમવા દેતા નહિં (ene ramavA detA nahiM )

(If said to a boy) Don’t let me eat:- મને ખાવા દેતો નહિં (mane khAvA deto nahiM )
(If said to a girl) Don’t let me eat:- મને ખાવા દેતી નહિં (mane khAvA detI nahiM )
(If said to an elder with respect) Don’t let me eat:- મને ખાવા દેતા નહિં (mane khAvA detA nahiM )