To do that you need the class active and inline style display: block;. Like the example below:
<section class="toggle active">
<label>International Code Council</label>
<div class="toggle-content" style="display: block;">
<p>The International Code Council offers unmatched technical, educational and informational products and services in support of the International Codes, with more than 250 highly qualified staff members at 16 offices throughout the United States and in Latin America. </p>
<p><a class="btn btn-primary push-bottom" href="https://www.iccsafe.org">More Info</a></p>
* Do this for each toggle section that you wants to starts opened when loads the page.
Please, try that and let us know if you need further assistance.