Ansense and other code with php conditional in byline

I am trying to learn these php conditional strings/codes, espcially after the newer Atahualpa, where you can't add stuff (like adsende) via the ATO.

As for now I need adsense to be in the Byline.

So far I've come up with:

I need this adsense code:
<script>blabla adsense blabla</script>

To be in this part in index.php
<?php bfa_post_byline('<div class="post-byline">','</div>'); ?>

Reading this forum over and over lets me know that I need something called
php conditional
And after looking there I think that i might be this one:
is_single() or <?php is_single($post); ?>

But the thing is, I just cant seem to figure out where/how in
<?php bfa_post_byline('<div class="post-byline">','</div>'); ?>
I should put both the adsense-script and the php conditional, I have tried a little here and there, but I get error when trying to load the page afterwards.

Can anyone tell me how the byline string should look like with the php conditional and the adsense script correctly inserted??

And from there I hope I can experiment on my own, with other kind of scripts and places in posts, I belive they work the same way.

Thanks