Please follow the instructions carefully, especially regarding your operating system. (We are not responsible for any errors/difficulties encountered).
Because the Greenfish Subtitle Player is a stand-alone application, there is no need to rename the srt files.

1) Install Greenfish Subtitle Player (and Net framework etc. if necessary)
2) Download the srt file(s) of choice to your PC. (Personal use only, please do not 'share' these without permission. Danke!)

1) Run the Greenfish Subtitle Player (you may get a warning statement ... click 'Run'- see image)

2) Open the srt file of choice by navigating to its saved location.

3) Click Pause on the Greenfish Subtitle Player.

4) Play the DVD and select either 'ALLES ABSPIELEN' (to view all), or 'FOLGENAUSWAHL'* (to select an episode - *recommended - see image)

Note: You may not be able to use Full Screen with Windows Media Player (WMP). Maximize the WMP view to allow for the subtitle player above or below.
Note: The subtitles do NOT include "Previously on Hand aufs Herz" nor do they include the Introduction. Wait for those to finish playing.

5) "Wrestling the alligator/crocodile" ... synchronizing the Greenfish Subtitle Player with the episode dialog is a bit of a challenge, but practice makes perfect. The time-codes are 'soft' (nearest 1/2 second) to accommodate synchronization issues.
     
Note: Use play/pause on either or both the media player of choice and/or the Greenfish Subtitle Player until either: the two time-codes match (see image) or the dialog matches.

Note) VLC & Media Player Classic 'may' render the time a bit differently. Additional synchronization adjustments during the episode may be necessary.

Good luck! Have fun! Stay Jemma!