You must have company admin and super admin access to create a manual install.
Click My Roles > EPC > Sales Organizations
Click on the "+New Install" button next to the company you want to add the install to.
Enter all of the customer's information and attach the PDF of the agreement. Click Continue. This will create a customer, deal, and install on behalf of your sales org
To create an install without contracts, follow the above instructions. Instead of attaching a PDF of the agreement, click the checkbox that says "Create New Install without Contracts." Click Continue.
This will create a customer, deal, and install without an uploaded contract on behalf of your sales org.