On click of arrow near Name - Account Number you will be prompted Account Settings in a Drop down menu as shown in below fig.
On Click on menu you will find account settings.
Click on edit, you will be prompted to edit Company Name, Address, Phone, Currency, TimeZone and the company logo
Fill all the information and browse your own company logo.
Click Save.
Total default staff will be 3, if you want to increase the number of staff kindly go on Subscription and Billing menu below the account setting tab.