Customization of the right side menu and popup window size

Dear experts,

I’m looking for someone who can customize the following:

1- one of the options on the right-side menu to be highlighted with a red background color, and hyperlinked (external link) to another site.

2- change the popup page size for mobile users (could be for mobile and PC users, whatever is easier for you)

I would be grateful if anyone could help with this urgently. Many thanks!

Please contact me directly at to discuss and agree.