Docs: Fix TestData docs (#22279)

* Update TestData docs

Fixes TestData docs by correcting name, installation instructions, etc. Should prevent issues like #16386.

- Fix name: `Grafana TestData` -> `TestData DB`
- Fix "Enable" section instructions
- Fix "Dashboard" section instructions
- Fix grammar

* Bold clickable items, list step-by-step instrs.

* Apply suggestions from code review

Co-Authored-By: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

docs/sources/features/datasources/testdata.md

@@ -9,36 +9,43 @@ weight = 20
 +++
 
 
-# Grafana TestData
+# Grafana TestData DB
 
-The purpose of this data sources is to make it easier to create fake data for any panel.
-Using `Grafana TestData` you can build your own time series and have any panel render it.
+The purpose of this data source is to make it easier to create fake data for any panel.
+Using `TestData DB` you can build your own time series and have any panel render it.
 This make is much easier to verify functionally since the data can be shared very easily.
 
 ## Enable
 
-`Grafana TestData` is not enabled by default. To enable it, first navigate to the Plugins section, found in your Grafana main menu. Click the Apps tabs in the Plugins section and select the Grafana TestData App. (Or navigate to http://your_grafana_instance/plugins/testdata/edit to go directly there). Finally click the enable button to enable.
+The `TestData DB` data source is not enabled by default. To enable it: 
+1. In the **Configuration** menu (small gear on the left side of the screen, click **Data Sources**. 
+
+1. Click **Add Data Source**.
+2. Search and click `TestData DB`.
+3. Click **Save & Test** to enable it.
 
 ## Create mock data.
 
-Once `Grafana TestData` is enabled you can use it as a data source in any metric panel.
+Once `TestData DB` is enabled, you can use it as a data source in any metric panel.
 
 ![](/img/docs/v41/test_data_add.png)
 
 ## CSV
 
 The comma separated values scenario is the most powerful one since it lets you create any kind of graph you like.
-Once you provided the numbers `Grafana TestData` will distribute them evenly based on the time range of your query.
+Once you provided the numbers, `TestData DB` distributes them evenly based on the time range of your query.
 
 ![](/img/docs/v41/test_data_csv_example.png)
 
 ## Dashboards
 
-`Grafana TestData` also contains some dashboards with example. `/plugins/testdata/edit`
+`TestData DB` also contains some dashboards with examples. 
+1. Click **Configuration** > **Data Sources** > **TestData DB** > **Dashboards**.
+1. **Import** the **Simple Streaming Example** dashboard.
 
 ### Commit updates to the dashboards
 
-If you want to submit a change to one of the current dashboards bundled with `Grafana TestData` you have to update the revision property.
+To submit a change to one of the current dashboards bundled with `TestData DB`, update the revision property.
 Otherwise the dashboard will not be updated automatically for other Grafana users.
 
 ## Using test data in issues