Improve "Installing the Knative CLI" (#2230)

* Make `install kn with Go` more detailed.
* Give example on how to run kn using container.

Author: MIBc

docs/install/install-kn.md

@@ -26,6 +26,26 @@ To install the `kn` Client, you must download the executable binary for your sys
 
 You must place the executable binary in your system path, and make sure that it is executable.
 
+## Install `kn` using Go
+**Prerequisite:** Building `kn` requires Go v1.14 or newer. You will first need a working Go environment.
+1. Check out the [Client repository](https://github.com/knative/client):
+  ```bash
+  git clone https://github.com/knative/client.git
+  cd client/
+  ```
+1. Build an executable binary:
+  ```bash
+  hack/build.sh -f
+  ```
+1. Move `kn` into your system path, and verify that `kn` commands are working properly. For example:
+  ```bash
+  kn version
+  ```
+
+## Install `kn` using brew
+
+For macOs, you can [install kn using brew.](https://github.com/knative/homebrew-client)
+
 ## `kn` container images
 
 The `kn` container images are available for users who require these for additional use cases. For example, if you want to use the `kn` container image with [Tekton](https://github.com/tektoncd/catalog/tree/master/kn).
@@ -34,3 +54,16 @@ Links to either the nightly container image or the latest stable container image
 
 - [Nightly container image](https://gcr.io/knative-nightly/knative.dev/client/cmd/kn)
 - [Latest release](https://gcr.io/knative-releases/knative.dev/client/cmd/kn)
+
+You can run `kn` from a container image. For example:
+  ```bash
+  docker run --rm -v "$HOME/.kube/config:/root/.kube/config" gcr.io/knative-releases/knative.dev/client/cmd/kn:latest service list
+  ```
+
+## Using `kn` with Tekton
+
+You can also [run kn using Tekton](https://github.com/tektoncd/catalog/tree/master/kn).
+
+## What's next
+To learn more about using `kn`, see the [documentation](https://github.com/knative/client/blob/master/docs/cmd/kn.md).
+