add line chart docs (#1321)

Co-authored-by: Hadar <[email protected]>

docs/customize-pages-dashboards-and-plugins/dashboards/dashboards.md

@@ -12,7 +12,7 @@ Dashboards are available in the following locations:
 
 ### Pie chart
 
-You can create a pie chart illustrating data from entities in your software catalog divided by categories and entity properties inside a specific entity page [**specific entity page**](../page/entity-page.md).
+Pie charts illustrate data from entities in your software catalog divided by categories and entity properties.
 
 ![Pie Chart](/img/software-catalog/widgets/pieChartExample.png)
 
@@ -29,10 +29,11 @@ You can create a pie chart illustrating data from entities in your software cata
 
 ### Number chart
 
-You can create a number chart visualization from related entities in the [**specific entity page**](../page/entity-page.md). 
+Number charts display a number value related to an entity and its properties.
+
 You can choose one of these chart types:
-* **Display single property** - display a property from a specific entity
-* **Count entities** - display the amount of related entities or showw average by time.  
+* **Display single property** - display a property from a specific entity.
+* **Count entities** - display the amount of related entities or show an average by time.  
 * **Aggregate by property** - apply an aggregation function on number properties from multiple entities. 
 
 :::note
@@ -92,6 +93,28 @@ When performing calculations of average time intervals, such as by hour, day, we
 For example, if the dataset includes information spanning across 2 hours and 20 minutes, but the selected average timeframe is `hour`, then the summed value will be divided by 3 hours.
 :::
 
+### Line chart
+
+Line charts display trends of `number` properties over time.  
+
+When creating a line chart, you need to choose a blueprint, then choose one of its entities, and finally choose one or more of the entity's `number` properties.  
+
+The chart will display the property values over the span of (up to) **one year** in daily intervals, with the x-axis representing the time and the y-axis representing the property values.
+
+For example, here is a line chart displaying a service's resource usage over a span of 8 days:
+<img src='/img/software-catalog/widgets/lineChartExample.png' width='100%' border='1px' />
+
+#### Line chart properties
+
+| Field         | Type     | Description                                   | Default | Required |
+| ------------- | -------- | --------------------------------------------- | ------- | -------- |
+| `Title`       | `String` | Chart title                                   | `null`  | `true`   |
+| `Icon`        | `String` | Chart Icon                                    | `null`  | `false`  |
+| `Description` | `String` | An optional description of the chart          | `null`  | `false`  |
+| `Blueprint`   | `String` | The chosen blueprint                          | `null`  | `true`   |
+| `Entity`      | `String` | The chosen entity                             | `null`  | `true`   |
+| `Properties`  | `Array`  | The chosen `number` property/ies to visualize | `null`  | `true`   |
+
 ### Markdown
 
 This widget allows you to display any markdown content you wish in formatted form: