in header.php =>
<?php
global $aFaQItems;
$aMeta =get_post_meta($post->ID);
//Extract FAQ items from faq custom fields
$aFaQItems=[];
if (isset($aMeta["faq"]))
	foreach ($aMeta["faq"] as $index=>$sFaq)
	{
		$sAnswer="";
		$sQuestion="";
		$iIndex =   strpos($sFaq, "?", 0);   //get pos of first question mark..
		if ($iIndex == true)
		{
		 	$sQuestion = substr($sFaq, 0, $iIndex );
			$sAnswer = substr($sFaq, $iIndex+1 );
			$aFaQItems[]=[$sQuestion, $sAnswer];
		}
		else
			continue;
	}

?>

also in header.php, before closing </head> tag 


<?php
	//Extract FAQ items from faq custom fields and echo the appropriate jsonld to the page..
	 
	if (isset($aMeta["faq"]))
	{
		echo '
		<script type="application/ld+json">
		{
			"@context": "https://schema.org",
		  	"@type": "FAQPage",
		  	"mainEntity": [
		';

		$iNumFaqs=sizeof($aFaQItems);

		foreach ($aFaQItems as $index=>$aFaq)
		{
	?>
			    {
			      "@type": "Question",
			      "name": "<?php echo $aFaq[0]?>?",
			      "acceptedAnswer": {
			        "@type": "Answer",
			        "text": "<?php echo addslashes(wpautop($aFaq[1]));?>"
			      }
			    }<?php 
		if(($index+1)!=  $iNumFaqs)
	   		echo ',';
		}
    	echo '
     
		 ]
		}
    	</script>';
	}
	
?>

in review template, or page / post template
<?php
 global $post, $aMeta;

?>


						<div class="row no-gutters" id="faqrowhome" style="">
							<div class="col-md-12 text-center">
									<h2 class="moduleheader" style="margin: auto; margin-bottom: 10px;">Frequently Asked Questions</h2>
								</div>
							 <div class="col-md-12 " id="">
							 	<?php
							 		foreach ($aFaQItems as $index=>$aFaq)
							 		{
							 		 
							 		 if ($index>1)
							 		 	$sIsExpanded="true";
							 		 else
							 		 	$sIsExpanded="false";
							 	?>
								  <div class="card">
								    <div class="card-header" id="heading-<?php echo $index;?>">
								      <h5 class="mb-0">
								        <button class="btn btn-link <?php  if ($index>1) echo 'collapsed';?>" type="button" data-toggle="collapse" data-target="#collapse-<?php echo $index;?>" aria-expanded="<?php echo $sIsExpanded;?>" aria-controls="collapse-<?php echo $index;?>">
								          <?php echo $aFaq[0];?>?
								        </button>
								      </h5>
								    </div>

								    <div id="collapse-<?php echo $index;?>" class="collapse <?php if ($index==0) echo 'show';?>" aria-labelledby="heading-<?php echo $index;?>" data-parent="#accordionExample">
								      <div class="card-body">
								       <?php echo wpautop( $aFaq[1],   $br = true );?>
								      </div>
								    </div>
								  </div>

								  <?php
									}
								  ?>
								
							</div>

						</div>
  
<?php

?>