Full screen images and editing the header

EDIT: So I realised that this is a request for general help, not really related to support for errors… if I’ve posted this in the wrong place feel free to move or close it! ??

Hi, I’m new to web design and after dozens of hours spent trawling relevant youtube videos and googling various questions, I would greatly appreciate help to achieve a few things using the Customizr theme.

1. I’d like to insert a full screen, responsive image on the homepage. Below this image (so upon scrolling down), I want to have a small section of content (written, and links to other pages). The background will be black.

2. I want to edit the header so that it is completely transparent (so the top of the aforementioned image will be behind the header menu), there is no default box within the header (the box containing the menu…essentially all I want are the floating menu options), and the menu options aligned in the middle, with the social link icons aligned to the right.

3. I’d like to know how to change the logo for each page, as the homepage will not have a logo whilst the other pages will have the normal logo.

Actually, a good example of what I’m after is a demo page for another, paid theme. However, I think that Customizr is a great theme and I’m fairly certain it’s fully capable of what I’m after. https://demo.qodeinteractive.com/bridge/
It’s a good example of my first and second questions, although it doesn’t really showcase the third. For the third question, this is a good example: https://www.audiomachine.com (compare with https://www.audiomachine.com/archive/ to see how the logo loads for a separate page).

Any and all advice is much appreciated, as I said earlier I’m new to all of this, so even if you provide one answer to one part of one question I’d still be very thankful. I’m not too familiar with CSS but would be perfectly willing to delve into it.

Cheers