doc: add Smartrest 1.0 guide

Signed-off-by: Rina Fujino <[email protected]>

Author: rina23q

docs/src/operate/c8y/smartrest-one.md

@@ -0,0 +1,73 @@
+---
+title: SmartREST 1.0 and basic auth
+tags: [Operate, Cumulocity]
+description: Establishing connection with Basic auth and using SmartREST 1.0
+---
+
+%%te%% supports basic authentication and [SmartREST 1.0.](https://cumulocity.com/docs/smartrest/smartrest-one/)
+This page explains how to use basic authentication and SmartREST 1.0 with Cumulocity.
+
+:::important
+It is highly recommended to use certificate-based authentication and SmartREST 2.0.
+This guide is intended for users who must use the SmartREST 1.0 for specific reasons.
+:::
+
+## Setting up basic authentication
+
+To use SmartREST 1.0, the authentication mode must be set to `basic` using the `tedge config` CLI tool:
+
+```sh
+sudo tedge config set c8y.auth_mode basic
+```
+
+Next, provide credentials (username/password) in a credential file formatted as follows.
+The default location of the credentials file is `/etc/tedge/credentials.toml`:
+
+```toml
+[c8y]
+username = "t5678/octocat"
+password = "abcd1234"
+```
+
+If needed, you can specify a custom location for the credentials file using the `tedge config` CLI tool:
+
+```sh
+sudo tedge config set c8y.credentials_path </custom/path/to/credentials.toml>
+```
+
+## Configuring the device ID
+
+The device ID must be explicitly set. This ID will be used as the external ID of the device in your Cumulocity tenant.
+
+```sh
+sudo tedge config set device.id <id>
+```
+
+## Adding SmartREST 1.0 template to %%te%% config
+
+You need to specify all the external IDs of the SmartREST 1.0 templates you plan to use.
+This can be achieved by providing a comma-separated list of the external IDs:
+
+```sh
+sudo tedge config set c8y.smartrest1.templates template-1,template-2
+```
+
+Alternatively, you can add the template IDs one by one:
+
+```sh
+sudo tedge config add c8y.smartrest1.templates template-1
+sudo tedge config add c8y.smartrest1.templates template-2
+```
+
+## Connecting to Cumulocity
+
+Before connecting to Cumulocity, ensure the following prerequisites are met:
+
+- The device has already been registered in Cumulocity using the [Bulk Registration API](https://cumulocity.com/docs/device-management-application/registering-devices/#bulk-device-registration).
+- The SmartREST 1.0 templates have been registered in your Cumulocity tenant.
+
+Once these steps are complete, you can connect to Cumulocity:
+
+```sh
+sudo tedge connect c8y
+```