Adminbit Question

[Sanctum]

<tr>
	<td bgcolor="$backcolor" nowrap><normalfont>
$onlinestatus</normalfont></td>
	<td bgcolor="$backcolor" nowrap 
width=100%><normalfont><b>
<a href="member.php?s=$session[sessionhash]&action=
getinfo&userid=$user[userid]">$user[username]
</a></b><br>$user[avatar]</normalfont></td>
<td bgcolor="$backcolor" nowrap><normalfont>$user[location]
</normalfont></td>
<td bgcolor="$backcolor"nowrap><normalfont>
$sendpmlink</normalfont></td>
</tr>

where its says $ user [userid ] how can I substitute this for a $ userinfo [ field x ] and get the information to show up?