@peerg
Within a toot, you find a submenu (three dots).
There, you find the option "pin to profile".
Should work that way :)
@peerg @fasnix weird. I don't think this is a matter of German vs English. Is that the web version or the app? If it's the app, can you try the PWA (the web interface, going to https://mastodon.social with your browser since that's your instanc,e logging in, and trying to pin it from there?)
If that's the new web interface, it might be a bug in. Mastodon.social often runs more bleeding edge versions of the software and maybe you tripped a bug?