Sorry to hear you find the tutorials at https://www.axcrypt.net/ counter-intuitive.
In this particular case, perhaps the main issue that you’re trying to do something that requires Premium functionality? You can try this for a month, for free, but the free version does not support it.
In order to securely share files securely, the sender needs at least Premium. You can compare versions and see pricing here: https://www.axcrypt.net/pricing/ . The recipient is fine with the free version.
Once the sender has Premium or better, follow the instructions in the video, or just right-click the file in the recent files list and chose the key sharing function, enter the recipients email and then send the updated file.