adjust zoom for google map on website

Google Maps Embed API indicates that you can use an optional parameter of zoom, or you can set up your URL to the zoom that you desire and then use that URL.

I saw that but where do I add?  My iframe doesn't look like their example.

<iframe style="border: 0;" src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d2879.076383608102!2d-87.95760399999999!3d43.812774999999995!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x880363b484bffb65%3A0x661fac2b01877773!2sW5228+Gerber+Lake+Rd%2C+Plymouth%2C+WI+53073!5e0!3m2!1sen!2sus!4v1430839076487" width="350" height="300" frameborder="0"></iframe>

The result you provided the map is too large
width="600" height="450"

I need map to fit
width="350" height="300"

I went to view larger map. Zoomed out 3 more levels. Grabbed the code.  Plunked it in site and it would not display.  Not sure why.

This is new code:

<iframe style="border: 0;" src="https://www.google.com/maps/place/W5228+Gerber+Lake+Rd,+Plymouth,+WI+53073/@43.812775,-87.957604,9z/data=!4m2!3m1!1s0x880363b484bffb65:0x661fac2b01877773?hl=en-US" width="350" height="300" frameborder="0"></iframe>

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This is old code that displays:

<iframe style="border: 0;" src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d2879.076383608102!2d-87.95760399999999!3d43.812774999999995!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x880363b484bffb65%3A0x661fac2b01877773!2sW5228+Gerber+Lake+Rd%2C+Plymouth%2C+WI+53073!5e0!3m2!1sen!2sus!4v1430839076487" width="350" height="300" frameborder="0"></iframe>

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Ah, you are correct.  I made the change and BINGO it worked!