Only an administrator in your account can do this.
Select Admin tab, then sub-contractors from the drop down box.
In the box enter Contractors Name, type the first letter of the contractor you are looking for and a list will appear, see screenshot below. Select the contractor and press enter.
Click the connect tab, and clixifix will prompt to ask you if you are sure you wish to add this contractor. Click yes to proceed.
The prompt will show that the contractor was added successfully.