Replace GRAV logo in the Skeleton "RTFM Site"

I installed the Skeleton "RTFM Site" from https://getgrav.org/downloads/skeletons
Please see https://demo.getgrav.org/rtfm-skeleton/
Question: How can I replace the blue GRAV logo on the top left side by the logo of our non-profit organization?

You need to extend partials/logo.html.twig template

Thank you for your fast response. I have no experience with Twig. Is there a way to gererate a twig file from a svg file containing the logo?

It can be an ordinary image too instead of svg. Eg.:

<img src="/some/image.png" alt="" />

Sorry, I'm not good at all in giving specific instructions 😃
Twig file is a simple HTML file with some Twig syntax if needed. In this logo case you don't need to know Twig at all

Now I switched to the template " "Learn2 Git Sync". Using this template, it is possible to replace the GRAV logo by the Site title. Now I have 2 other quiestions:

1. How can I get rid of the text "Built with <a href="http://getgrav.org">Grav</a> - The Modern Flat File CMS" at the bottom of the sidebar.
2. How can I change the text "Search Documentation" in the search box at the top of the sidebar.
   (see screenshot)

If you check the theme templates, you'll find in partials/search.html.twig and partials/sidebar.html.twig the language constants you need to extend and change to your liking. It's THEME_LEARN2_SEARCH_DOCUMENTATION and THEME_LEARN2_BUILT_WITH_GRAV

Mr./Mrs. Karmalakas, your support is just great. Thank you so much for your fast response.

@ADemmler, To show karmalakas your gratitude, you could consider ticking the love/like icon in the lower-right corner of each and every reply you appreciate...

And another good practice on the forum is to tick the 'solution' icon of the reply that answers the original question as posed in the title. That may also be your own reply...