Form contact in mache template

Hi All,
I don’t get something related to the form.

I take the mache template which seems pretty good.
In the skeleton provided , there is a modular page with in it a subpage template contact.

I would like the “contact” in a simple page.

I have first try to duplicate the page from the skeleton and delete all the modular that i don’t want.
I keep the contact subpage with :
"title: Contactme
cache_enable: false
onpage_menu: false
items: '@self.modular
by: default
dir: asc
- _banner
- _contact
action: /home
name: contact"
and so on
In this case, i lost all the header included the menu.

After that i have duplicated the form.html.twig from antimaster to mache in order to create a form page with :
"title: ContactForm
cache_enable: false
onpage_menu: false
name: contact-form
and so on
I lost also my header , i still have my menu with a little display default.

Finally, how can i keep all my header ? What i don’t get in ?

Thanks for your help.

I am not sure that is the right way but to share one solution, i have had in the form.html.twig :
"{% if theme_config.default_background_image|length > 0 %}
{% for item in theme_config.default_background_image %}
{% set image = %}
{% endfor %}
{% endif %}

{{ page.title }}

{{ page.header.summary }}
{{ page.content }}