added steps for adding instances

Author: travisamartin

content/nim/nginx-instances/add-instance.md

@@ -0,0 +1,39 @@
+---
+title: "Add an NGINX instance"
+weight: 100
+toc: false
+nd-content-type: how-to
+nd-product: NIM
+---
+
+This guide shows you how to add NGINX Open Source and NGINX Plus instances to F5 NGINX Instance Manager.
+
+## Before you begin
+
+Make sure you have:
+
+- One or more instances running NGINX Open Source or NGINX Plus.
+- Admin access to NGINX Instance Manager.
+
+## Add instances
+
+1. Open the NGINX Instance Manager web interface and log in.
+2. In the **Manage** section on the left, select **Instances**.
+3. Select **Add**.
+4. Copy the `curl` command.
+5. On the host where your NGINX instance is running, run the `curl` command to install NGINX Agent:
+
+   ```shell
+   curl https://<NIM-FQDN>/install/nginx-agent | sudo sh
+   ```
+
+6. On the same host, run the following command to start NGINX Agent:
+
+   ```shell
+   sudo systemctl start nginx-agent
+   ```
+
+## Next steps
+
+- [Add instances to instance groups]({{< ref "nim/nginx-instances/manage-instance-groups.md" >}})
+- [Add managed certificates]({{< ref "nim/nginx-instances/manage-certificates.md" >}})