ZWave Installation where is config.txt?

I try to install zwave on The manual says:

If you need GPIO on raspberry-pi3 for you Z-Wave module add follow line into config.txt:

But where is the config.txt file and how can I get access to the file?

Thanks for your help


or put your card in another computer - It’s a FAT32 partition on the memorycard.

Thank you!

How may I mount the partition on my Mac or on my other Pi with Rasbian?