This article is about the Proxi admin app at app.proxi.co.
On Google Sites, the simplest route is to embed your Proxi link directly. Google Sites frames it for you.
Steps
In Proxi, copy the link from the Link tab of the Share dialog. For an experience sign-up form, add /register to the end of the experience link.
In Google Sites, choose Insert → Embed, stay on the By URL tab, paste the link, and insert it.
Drag the corners to size it. A map wants most of the page width and around 600 pixels tall.
Publish.
A Whole Page for Your Map
To give the map its own page in your site's menu, use Pages → + → Full page embed and paste the same link. The map fills the page.
Good to Know
The Embed code tab also accepts the Proxi embed code, but Google Sites runs it inside its own frame, so the URL route is more predictable.