You can add Leads in bulk or can create them individually. To add a new single Lead, you will notice a + New Lead button (its red) in the upper right corner of the Home page or on the Leads page. Once selected, you can input the Lead's information. Note, you must include a first name and last name. 

Once you complete the information, you can submit or submit and create another Lead. Either way, the Lead you just created will be added to your Lead list (navigate there by click "Leads"). 

If you want to upload Leads in bulk click on the dropdown under the +New Lead button in the upper left corner (see screen shot below). Click "Import Leads"

Video Tutorial