New Collection: How to add fields?

Hi,
I can’t figure out how to add fields in a new collection. In the docs I see a button [+ add field]. In my install this button is nowhere to be seen and no way to add a field. How can this bi accomplished? Is there an alternative way than through the Webinterface?

Screenshot: https://ibb.co/ctq70C9

thanks! Valentin

How I got there:
I made a fresh install (v. 0.8.7), the /config and /storage folders are readable by the webserver, added an admin user and created a new collection. Double checked all requirements.

Weird… Which browser did you use?

Add a file to /storage/collections/collectionname.collections.php and add your field definitions as PHP array.
Examples: