Firstly make sure to LOG in to the Salesforce account.
Go to "setup" located in the upright corner.
Click "Create" and select required "OBJECTS" under the BUILD section.
Now you have to create a custom object. Go to "New Custom Object" and enter its name in the Object Name, Label, and Plural Label.
On the bottom-left part of the window, you will see a checkbox "Launch New Custom TAB Wizard after saving this custom object". Select it and click on the "save" button.
Click the SEARCH icon to select an icon for the tab and click next.