With this little bit of code below, you can dynamically display a specific Data Collection Item using the Web Page's name tag {bb_pagename}.
For example, let's say you wanted to have a custom image at the top of your subpages with having to hardcode the IMG tag on each Web Page. You can place a {bb_datacollection} tag on a Page Template that you assign to your Web pages. Using the 'filter' parameter in your {bb_datacollection} tag to filter only one specific Data Collection item that has a matching name.
Sample tag
{bb_datacollection source="Page Header Photos" filter="Item_Name:{bb_pagename}"}
Sample Page Template
<!DOCTYPE html>
<head>
{bb_siteheader}
{bb_pageheader}
</head>
<body>
{bb_datacollection source="Page Controller" filter="Item_Name:{bb_pagename}" layout="Page Header"}
{bb_webpagecontent}
{bb_sitefooter}
{bb_pagefooter}
</body>
Data Collection Custom Layout
This assumes you created a Data Collection 'Image' field called "Page Photo".
<img src="{{page_photoUrl}}" alt="{{dataNameNoLink}} header photo" />
During rendering the final HTML will output this code.
<img src="service-header.jpg" alt="Services header photo" />