Log in to your Jenkins server, and from your home dashboard, click on Manage Jenkins. 

Then, on the Manage Jenkins page, select Manage Plugins from the list, as follows:

The credentials plugin is required, but should be installed by default. We can check the Installed tab if in doubt, as shown in the following screenshot:

Next, let's click on the Available tab. The Kubernetes plugin should be located under Cluster Management and Distributed Build or Misc (cloud). There are many plugins, so you can alternatively search for Kubernetes on the page. Check the box for Kubernetes plugin and click on Install without restart. This will install the Kubernetes plugin and the Durable Task Plugin:

If you wish to install a nonstandard version, or just like to tinker, you can optionally download the plugins. The latest Kubernetes and durable task plugins can be found here:

• Kubernetes plugin: https://wiki.jenkins-ci.org/display/JENKINS/Kubernetes+Plugin
  
• Durable task plugin: https://wiki.jenkins-ci.org/display/JENKINS/Durable+Task+Plugin
  

Next, we can click on the Advanced tab and scroll down to Upload plugin. Navigate to the durable-task.hpi file and click on Upload. You should see a screen that shows an installation progress bar. After a minute or two, it will update to Success.

Finally, install the main Kubernetes plugin. On the left-hand side, click on Manage Plugins and then the Advanced tab once again. This time, upload the kubernetes.hpi file and click on Upload. After a few minutes, the installation should be complete.