Click on the Add/Search menu, select Individual.
On the Individual Search screen, enter in the name of the individual you would like to add. 
Click the Search button. You will move on to the Search Results Individual screen. If any existing records matched the data you entered, those contacts will be listed. If you find the person you were trying to enter, click the Use button next to their entry. In this case, you will be editing an existing record rather than adding a new contact. See editing an existing individual.
You will also see three buttons at the bottom of the screen:
Add Individual - this button is if you are entering only personal data for your new contact.
Quick Add &endash; New Individual & Expense - this button is if you are entering a new record for someone to whom your organization has issued a financial transaction.
Quick Add &endash; New Individual & Contribution - this button is if you are adding a new record for someone from whom your organization has received funds.
Select which Add button you need and click it.
The View Individual screen will appear. The data you entered in the Add/Search fields appears in the appropriate information area below. You can now enter all of the additional contact information you have for this contact, including their address, phone number, e-mail address and other miscellaneous information. Be sure to click the Save Changes button before you leave this screen in order to add this record to your database.
For more about the View Individual screen, click here.