You need to use custom xfields
http://www.mywebsite.com/admin.php?m...tion=configure

Add them in your template then like. You can use [xfvalue_myfieldname] to get its value.

Eg:
Field name: poster
PHP Code: 
[xfgiven_poster]<img src="[xfvalue_poster]" />[xfgiven_poster]