Create Forms in Drupal and process them
I'm assuming that you're using Drupal7.  I will provide some pointers but you'll have to look up the details on your own.


Sounds like you might want to create a new Content Type.
Views can generate a list of a specific Content Type (in your case, list only seminars).
Views typically links each item in the list to the actual node with the full info
The Webform module will allow you to create sign up forms but there's likely more that you'll have to do to tie everything together.