Accounts and Contacts are where you keep track of your customers. Accounts are generally companies and contacts are the people that work at those companies. You cannot create a contact without an account. If your accounts are individuals and not companies, you can simply use the contact name as the account name, or the contact street address and their name - Smith 123 Residence Lane.
You can bulk import your existing accounts and contacts at the same time from a csv file using the Bulk Import button that is on the Account list view page.
On the account and contact main list views, you can toggle, rearrange and resize columns. You can also merge, bulk update, bulk delete and export by using the selection check boxes on the left of each row.
On the account and contact detail pages, all of the standard fields are displayed and any custom fields you created in company settings. You can rearrange the way these fields are displayed by using the Customization/Widget fields tab under Company Settings.