The AIDA model describes a four-step process that your target market undertakes before taking action (buying your product or service). You as a marketer should encourage your target market to take the next step in the process.
Step 1: Attention
Your target audience must be aware of your offer, so you should get their attention.
Step 2: Interest
You should catch their interest in your offer.
Step 3: Desire
It must be irresistible to them so that they desire to have your product/service.
Step 4: Action
You must provide the ability (and encourage them) to take action.