here i am giving your code to do with your above specification you can set it in to your html
1. Product description
$_product = Mage::getModel('catalog/product')->load(PRODUCT_ID);
echo $_product->getShortDescription(); //product's short description
echo $_product->getDescription(); // product's long description
2. product tags
$model=Mage::getModel('tag/tag');
$tags= $model->getResourceCollection()
->addPopularity()
->addStatusFilter($model->getApprovedStatus())
->addProductFilter(PRODUCT_ID)
->setFlag('relation', true)
->addStoreFilter(Mage::app()->getStore()->getId())
->setActiveFilter()
->load();
if(isset($tags) && !empty($tags)):
foreach($tags as $tag):
echo '<span class="tag">'.$tag->getName().'</span>';
endforeach;
3. Product Reviews
$productId = $product->getId();
$reviews = Mage::getModel('review/review')
->getResourceCollection()
->addStoreFilter(Mage::app()->getStore()->getId())
->addEntityFilter('product', $productId)
->addStatusFilter(Mage_Review_Model_Review::STATUS_APPROVED)
->setDateOrder()
->addRateVotes();
4.contain a specific cms page
I would like to suggest you if you want to display product specific content you can create block for product and in phtml file you can call like below
echo $this->getLayout()->createBlock('cms/block')->setBlockId('your-block-id')->toHtml();
Also you can refer detail page
hope this will sure help you.