Add dev docs about usage

Signed-off-by: Alexandr Demicev <alexandr.demicev@suse.com>

README.md

@@ -10,7 +10,59 @@ Currently this project has the following functionality:
 
 ## How to use this?
 
-Instructions coming soon :)
+### Installation
+
+```
+Note: The following will only work after we release the first version of the extension.
+```
+
+Prerequisites:
+
+- Running [Rancher Manager cluster](https://ranchermanager.docs.rancher.com/) with cert-manager
+- [Helm](https://helm.sh/)
+
+Quick start:
+
+These commands will install: Rancher turtles extension, CAPI Operator, and the core CAPI CRDs and controllers.
+
+```bash
+helm repo add rancher-turtles https://rancher-sandbox.github.io/rancher-turtles
+helm repo update
+helm install rancher-turtles rancher-turtles/rancher-turtles --create-namespace -n rancher-turtles-system
+```
+
+Customizing the deployment:
+
+The Rancher turtles Helm chart supports the following values:
+
+```yaml
+rancherTurtles:
+  image: # image to use for the extension 
+  tag: # tag to use for the extension
+  imagePullPolicy: # image pull policy to use for the extension
+  namespace: # namespace to deploy to (default: rancher-turtles-system)
+capi:
+  enabled: # indicates if core CAPI controllers should be installed (default: true)
+  namespace: # namespace to create and deploy core CAPI controllers (default: capi-system)
+  configSecret:
+    name: # name of the config secret to use for core CAPI controllers, used by the CAPI operator. See [CAPI operator](https://github.com/kubernetes-sigs/cluster-api-operator/tree/main/docs#installing-azure-infrastructure-provider) docs for more details.
+    namespace: # namespace of the config secret to use for core CAPI controllers, used by the CAPI operator.
+  fetchConfig: # (only required for airgapped environments)
+    url: # url to fetch config from, used by the CAPI operator. See [CAPI operator](https://github.com/kubernetes-sigs/cluster-api-operator/tree/main/docs#provider-spec) docs for more details.
+    selector: # selector to use for fetching config, used by the CAPI operator.
+cluster-api-operator:
+  enabled: # indicates if CAPI operator should be installed (default: true)
+```
+### Installing CAPI providers
+
+The Rancher turtles extension does not install any CAPI providers, you will need to install them yourself using [CAPI operator](https://github.com/kubernetes-sigs/cluster-api-operator/tree/main/docs).
+ 
+To quickly deploy docker infrastructure, kubeadm bootstrap and control plane providers, apply the following:
+
+```
+kubectl apply -f https://raw.githubusercontent.com/rancher-sandbox/rancher-turtles/main/test/e2e/resources/config/capi-providers-secret.yaml
+kubectl apply -f https://raw.githubusercontent.com/rancher-sandbox/rancher-turtles/main/test/e2e/resources/config/capi-providers.yaml
+```
 
 ## How to contribute?
 See our [contributor guide](CONTRIBUTING.md) for more details on how to get involved.
@@ -68,4 +120,4 @@ What happens when you run `make dev-env`?
 
 ## Code of Conduct
 
-Participation in the project is governed by [Code of Conduct](code-of-conduct.md).
+Participation in the project is governed by [Code of Conduct](code-of-conduct.md).