How do I get the Global Site Search widget onto my sub sites?

I have a main site. It is nothing more than a landing page with two options:

Go to site A (consumer) | Go to site B (Vendor)

Site A then has links to multiple stores.

I am using Panino as the (much modified) theme for Site A

I have loaded the ONLY available search widget onto the Site A home page. BUT it is just the bog standard single site search function.

How do I get the GLOBAL search widget to me sub-site/s???

If you need to look at the flow, go to http://diymarket.place

Thanks,

David Wilks