If you want to upload your own background image to funeral templates, first you should be on home page and then scroll down the page and click on Start Now button.
It will open funeral card templates page then you have to enter deceased person details and click on Start Design button.
After that it will open login/signup page if you are a new user then you should signup first other wise you can login and then it will open customization tool where you can customize your template as per your requirement.
To upload your own background image, click on the button named Upload Your Background Image to complete upload background image then it will open your system file then select background image from your system and upload. If you want to more detail about it then you can watch video tutorial which is given above.