It sounds as if you were trying to install Official TWRP App - this actually does a quite different job from Recovery.
You can simply boot into Recovery mode, to see if you have TWRP. If you find that you have /e/ Recovery, perhaps see if the process still looks intuitive with the information you have.
The process is covered in this tutorial (the link aims to drop you in at (8) Install /e/ without computer from your device, with TWRP using the SDcard method > sub section B) Transfer the /e/ ROM to the internal storage of the smartphone
As usual, please backup all your data first. Any problems please ask again.