Theme development

I am new to Drupal and am editing a site for a new client. The client would like a footer added and from what I've read in my research I should do this through the Structure > Blocks function. Problem is, I am not showing the Blocks function as an option here. It was built in Drupal 7 so this may be the issue? The only options I'm given under the Structure tab are:

-Content Types

-Features

-Menus

-Panels

-Mini Panels 

-Taxonomy

-Views

-Contact Form

I have an autoplaying looping video on my site's home page.

this is the twig code used to render it:

My Drupal 8 Site report is giving this Media warning:

It is potentially insecure to display oEmbed content in a frame that is served from the same domain as your main Drupal site, as this may allow execution of third-party code. You can specify a different domain for serving oEmbed content here.

 I've been searching various forums and reading Drupal documentation but I cannot find an explanation for how I can fix this warning?

Hi, I'm using Drupal 8.8.1

I created a module for generate rss feed. I created an twig template file podcast-rss-feed.html.twig under templates folder , below is my code:

I have webform with fields: name, phone and hidden field product.
For hidden field I use token [current-page:title]
Alll pages of pruduct have the button that pops up a webform.
When submitting a form I would expect that [current-page:title] returns title of the current product page I'm currently on. Instead it points to webform title.
Please tell me how to get a real title?

I need replace field value to some text if value equal 0
in node--new_material.html.twig

{{ content.field_cena }} - it displays the value

These filter versions don't work

{{ content.field_cena|replace({'%0%': 'some text'}) }}
{{ content.field_cena|replace('0', 'some text') }}
{{ content.field_cena.0|replace({'%0%': 'some text'}) }}
{{ content.field_cena.0|replace('0', 'some text') }}

nothing is displayed.

Please tell me the solution!