BACKGROUND IMAGE IN CONTACT FORM

Site URL: https://www.guilledelcastillo.es/contacto

Hi guys, i've tried to put an background image in my contact page. As you can see, in my home page (www.guilledelcastillo.es) I have two background image (at the top and just above the instagram block) with the "Banner" metod/option. But... first, i dont want that the background image have movement and... second,  I dont want that in the contact page the bakcground image invade the first navigation and the logo site (this is what happens when you put the background image with the banner option)

How i could resolve this?

@tuanphan and foro thanks guys 

Thanks u guys. An example make with Photoshop. I want this: 

Add to Home > Design > Custom CSS

body#collection-58446b8729687f59fe61dd54 .Main.Main--page {
    background-image: url(https://beaverhero.com/wp-content/uploads/2019/12/squarespace-2-languages-sites.png);
    background-size: cover;
    background-position: center center;
    background-repeat: no-repeat;
}

Thanks you so much @tuanphan works perfectly. I have another question... One hour ago (after set up the contact page) I have set up the primary nav on the TOP left and the logo on the top right. This morning the place of the primary nav and my logo was set up on button left and button right... 

As a result of this change ... the main image of my website has changed its appearance. I attach two images to you. I want to be able to have the configuration in TOP LEFT AND TOP RIGHT and that the image looks like BUTTON LEFT and BUTTON RIGHT. Its possible? Only with the main page picture. Thank you so much for your help. U are a master!!!!

Set up in TOP (nav and logo)

Set up in BUTTON (nav and logo) 

I want set up in TOP but the same apparience of my main page (picture) as BUTTON set up.