Hello Stephen,

It's difficult to point you in the right direction, so I will guide you to some tips that should help you out, so check these out if you still have trouble then mention where you want to do what and why it does not work, a prtscrn is ussually very helpfull for us to help you.

There is alos info in the guides section here and in the help file (press F1 wherever you are in x5, check also the best practice in the help file for very good tips and guides)

The page normally does not fill the browser window, only background options can do that. you can set them on several places;

For the template goto step2 tamplate customization, then select template structure, on the left you can select with the colour bars wich viewport you are checking, set page selection to page background, and set a picture. if you want a pictuure set colour to transparant.

For the page:

Goto step3 select the page and use on the right propertiies button. Then goto graphics TAB there you can set a picture or colour for background on this page.

For objects on your page:

goto step4 select the object and goto row formats button then choose image.

Here are some links that might help you:

https://helpcenter.websitex5.com/fr/post/111985

https://helpcenter.websitex5.com/en/search/type%3Aguides

https://helpcenter.websitex5.com/fr/post/169726

https://helpcenter.websitex5.com/fr/post/159924

Goodluck