Canyon strive cf8 shapeshifter question

Hi I’m all new to the game, I’ve bought myself a used canyon strive cf8 with a shapeshifter. But I’m not entirely sure how to use it. It has two modes, black light and green light. If I press the shapeshifter without standing on the bike the light gets green and the shapeshifter pulls out, if I’m standing on the bike and do a compress while pushing the button the shapeshifter retracts and the light is black. What mode shall I use for pedaling uphil and what shall I use downhill?

Love the sport, been on the bike for 1 month now and absolutely loves it. It was a childhood dream to do enduro/downhill but as I grew older it just disappeared, now 20 years later in the age of 32 I moved with a track in my backyard, and I had to get a bike. Having some progress as well 🤩🙌🏼