In grantee's portal, under requirements, click on the one you would like to submit.
Enter the required information.
For uploading the attachments, make sure to do the followings in order:
1- Click the "Browse" button and choose the file you would like to upload.
2- Click the "Upload" button, otherwise, it will NOT be attached and will not be sent out and WPP will not receive them. They are gone for good.
You can either save the requirement and continue to work on it later, or if you are done and happy with the form, you can "Review & Submit" the form.