Unable to install OwnCloud 10 on Ubuntu 18.04



I am trying to install OwnCloud on Ubuntu on AWS EC2. I am following this URL to install: https://download.owncloud.org/download/repositories/stable/owncloud/index.html

My ubuntu version is 18.04. I did first 2 steps (wget and echo) and when I tried to do apt-get update, this is the error I recieve:

    ubuntu@ip-172-xx-xx-254:~$ sudo apt-get update
Hit:1 http://us-west-2.ec2.archive.ubuntu.com/ubuntu bionic InRelease
Hit:2 http://us-west-2.ec2.archive.ubuntu.com/ubuntu bionic-updates InRelease  
Hit:3 http://us-west-2.ec2.archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:4 http://ppa.launchpad.net/ondrej/php/ubuntu bionic InRelease              
Get:5 http://security.ubuntu.com/ubuntu bionic-security InRelease [83.2 kB]    
Ign:6 https://attic.owncloud.com/org/download/repositories/production/Ubuntu_18.04  InRelease
Get:7 http://download.owncloud.org/download/repositories/production/Ubuntu_18.04  Release [984 B]
Get:8 http://download.owncloud.org/download/repositories/production/Ubuntu_18.04  Release.gpg [481 B]
Ign:8 http://download.owncloud.org/download/repositories/production/Ubuntu_18.04  Release.gpg
Reading package lists... Done
W: GPG error: http://download.owncloud.org/download/repositories/production/Ubuntu_18.04  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 47AE7F72479BC94B
E: The repository 'http://download.owncloud.org/download/repositories/production/Ubuntu_18.04  Release' is not signed.

I am stuck here with no documents helping me. Any immediate help would be really appreciated.


Did you skip the

apt-key add - < Release.key