Ok lets make the instruction easier. First I advice you use FileZilla client for downloading and uploading the files on your site. Obviously you need FTP credentials, if you don't have an FTP credentials please contact your hosting and ask how you can get one.
Now, after you've login to your server via FTP navigate to this directory
On that folder download the file _brand.php, open/edit that file with your favorite text editor (no not MS Word), if you don't have any text editor yet, you can download the free sublime or the notepad++
On that file you'll see this block of code.
<a href="<?php echo home_url( '/' ); ?>" class="<?php x_brand_class(); ?>" title="<?php echo $site_description; ?>">
<?php echo ( $logo == '' ) ? $site_name : $site_logo; ?>
That is the block that outputs the logo.
So you just need to duplicate that block but in a static HTML format. Take that code below as example:
<a href="SITE URL HERE" class="<?php x_brand_class(); ?>" title="">
<img src="LOGO URL HERE" alt="SOME ALTERNATIVE TEXT HERE">
Examine that code and give what it is asking for. You can add multiple of that if you need to, then save.
Then after you finish editing that file, go back to your FTP and navigate to this directory
If that directory does not exist then create the folders, make sure its the exact folder names. After you've created that directory upload the edited _brand.php there.
Then make sure your child theme (in Appearance > Themes) is active and you clear your browser's cache and any caching plugin you might have before you preview the site.
Hope it helps,