To have a link on header image you need to customize header.php template keeping on child theme. This will prevent your changes to be lost on theme update.
And for root directory link, you can take this function as a reference.
Note: Please start customizing theme only if you are technically sound on WordPress, on this case we recommend you to take help of professional WordPress Developer.
You can do like that but you have to make position of link to absolute and add some more css to make it working . You can take this code for a reference: <a href="<?php echo esc_url( home_url( '/' ) ); ?>" style=" width: 100%;font-size: 25px;color: #000;position: absolute;top: 137px;text-align: center;">click anywere!</a>
As this involves customization work, please take a help from a developer or you can send your quote for customization work at [email protected]