Click on "New Store" button and you will get a screen as shown below. From here for "Store Type " choose "Web Store /Product Channel" and fill in other fields: for example for
Store Number - you can use the next free number
Name - you can use "Main Web Site"
Short Name - you can use "WEB1"
As soon as all fields are put down click on "Continue" button.
After clicking "Continue" button you will get a page like this.
The following drop downs should be automatically filled in:
If these drop downs are empty and there is no suggestion to choose, follow these steps.
Navigate to Store Operation > Linked Apps > Magento Instance > Magento API Settings > click to edit the API and click "Save" button.
After go on filling the requested fields. For example for:
Register Unique ID - WEB_1
Register Name - Web Sales
Store Email (Admin Email) - your admin email
After all these are done click "Save" Button