You may place the sections placeholder anywhere you like in the template. By default, we placed sections at the top and bottom of the template and named them accordingly. Your templates/product.liquid file looks like this:

n order to create a new zone for sections called "middle" between the product tempate section and related products section, you would add
{% include 'atb' zone: 'Middle' %}
e.g.
{% include 'atb' zone:"Top"%}
{% section 'product-template' %}
{% include 'atb' zone: 'Middle' %}
{% section 'related-products' %}
{% section 'recently-viewed-products' %}
{% include 'atb' zone:"Bottom"%}
If you wanted to be even more specific and place the zone inside one of the sections, you would have to pull the section code out into the main template we only parse the main template file for zones.