Shopify Widget Rendering


I am looking for some assistance in placing the html within my shopify theme for the shopify merchant bridge. I have added two snippet pages to the snippets section for the connect and campaign widgets, and at this point need to add the javascript and css snippets to the header of my site as well as render the widgets to the product page template.

Some of my preliminary questions are as follows:

Would I be using the header of the “theme.liquid” file which is located in the Layout section of my themes code?
Should I be placing the html that renders the widget into the template itself, or should I use the visual editor and place a html block to paste it into?

My big issue is I am not too familiar with liquid, and want to make sure that I get a grip on this before moving to implement in my live site. I would ultimately like a dev to handle this for me, someone I can call on as a point of contact to help with some of the campaigns if needed in the future as well. Hope to hear back!