HELP php variables outside

[hhss]

how can I use php variables in xenforo template, which php we should use ? We will make extra definition from outside
https://puu.sh/vHPdi/0de453339a.png

I use only forums home page.

I use this code:

<xen:if is="{$visitor.user_id}">
<title><xen:if is="{$title}">{xen:raw $title} | {$xenOptions.boardTitle}<xen:else />{$xenOptions.boardTitle} MH {$mycodeishere}</xen:if></title>
<xen:else />
<title><xen:if is="{$title}">{xen:raw $title} | {$xenOptions.boardTitle}<xen:else />{$xenOptions.boardTitle}</xen:if></title>
</xen:if>

and I can't how make {$mycodeishere}
https://puu.sh/vHRT9/cf6c696545.png I' can't import