ましょう is one of the conjugations of the auxiliary verb ます, and is a common (polite) way to suggest that something be done 'together' (when used with a verb). It is often translated as 'let's (A)', or 'shall we (A)?'. To use ましょう, we will simply need to change ます to ましょう, when conjugating the verb.

• モールに行（い）きましょう！
  Let's go to the mall!
• 踊（おど）りましょう。
  Shall we dance? (Said with a rising tone to indicate that it is a question)

Despite regularly being translated as 'shall we (A)?', ましょう does not specifically target another person, and can also be used as a declaration that (A) will be done/needs to be done. This use reflects the base meaning of ましょう, which is the polite volitional form (deliberately/purposefully doing something).

• ５キロ痩（や）せましょう！
  I will lose 5 kg! (I shall do it!)

In this example, the speaker is expressing to themselves that they 'will' do something, and are strongly resolved to make it happen (similar to 'I shall' in English).