MyBB Community Forums

I have my discord premade widget link. how do i install this on my forums page. I am very new to using mybb, sorry if this is a stupid question
i am currently using flatty them and would like it to be under whos online

navigate to below location
forum admin panel >> Templates & Style >> Templates >> Flatty Templates >> Index Page Templates >> index
find code like below

<tr>
<td class="trow1">
{$whosonline}
</td>
</tr>

add below code after above given code & save the template

<tr>
<td class="trow1">
your widget code here
</td>
</tr>

see also templates guidance