Jenkins isn’t part of the repositories for Ubuntu 19.10 but can be easily installed after adding it. Steps below:
Download and add the key
wget -q -O - https://pkg.jenkins-ci.org/debian-stable/jenkins-ci.org.key | sudo apt-key add -
Add the repo to the sources file
echo deb http://pkg.jenkins-ci.org/debian-stable binary/ | sudo tee /etc/apt/sources.list.d/jenkins.list
Update
sudo apt update
Install Java
sudo apt install openjdk-8-jdk
Install Jenkins
sudo apt install jenkins
Start the Jenkins service
sudo systemctl start jenkins
Access the Jenkins installation via a browser at: http://<ip_address>:8080
Admin password
Access the admin user password as per the below
cat /var/lib/jenkins/secrets/initialAdminPassword