5/6 adding the link

I’m not sure what I’m doing wrong here.

Have a read through
= https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a
and have close look at the definition of the opening a-Tag
( there is NO /-sign at the END-OF-opening-A-tag )
so change your

 <a href="http://www.twitter.com"/>


 <a href="https://www.twitter.com">

u had a / at the end

Bingo ! Thanks for the advice!