Not trying to hijack Rocio’s thread. Just want to answer Dan’s question…
Neither.
Etcher doesn’t push or pull data. It writes the data directly to media physically connected to
the computer it’s running on. e.g. a card in a built-in SD slot or USB-SD card reader.
Here’s what you do:
Remove the µSD card from the RPi and insert it into your laptop or a USB card reader
if no SD card slot is available. I put a link to an example of a reader in your thread.
(https://community.openenergymonitor.org/t/really-basic-set-up-for-emoncms-and-raspberry-pi/18329/14)
Write the image file to the card with the app of your choice. e.g. Etcher, RasPi Imager, WinImage, etc.
Put the card back in the RPi.
Boot your RPi and continue from there.
Hope that answers your question and clears the confusion. 