For the sideload you got to connect the phone with your PC via usb.
Then these are the steps following the guide:
"* In TWRP return to main menu, then tap
- Now tap
Format Data and continue with the formatting process.Here a new screen may show where you will have to type
Yes and confirm the action by clicking a button.
Caution: Format Data will remove encryption as well as delete all files stored on the internal storage. Remember to take a backup first. Check Requirements section above.
- Return to the previous menu and tap
- Select the
System partitions to be wiped and then
Swipe to Wipe
- Sideload the /e/ .zip package.
Tip: Sideload requires actions in two places to be done. One on your phone in the TWRP UI and secondly on the connected PC which should have adb enabled. Also note the sideload process while running may stop abruptly around 50%. The console would show a message
Total xfer: 1.00x. This would mean that the transfer has successfully completed.
ADB Sideload, then swipe to begin sideload."
This is on the PC in Terminal:
- On the host machine, in the console , start the sideload of the package by typing
adb sideload filename.zip
You got change into the folder which contains the zip-file (cd…) or paste the whole path (for example “/home/YOURUSERNAME/Downloads/FILENAME.zip”)
Tip: Change the filename to the name of the file you downloaded
- Once installation has finished, return to the main menu, tap Reboot, and then System"