If you have already a .csv file containing the contact information you need to import proceed to the Step 2.
If you store your contact information in a spreadsheet, check it and save to a CSV (Comma Separated Values) file format, for example using the Documents module.
Each spreadsheet row should correspond to a single contact record. The first row can be a header record containing column/field names. Each contact record should contain the following required fields: First Name, Last Name and Email.
You can also create a new spreadsheet directly on your portal.