Update planner overview documentation for clarity

Author: JarbasHorst

api-reference/beta/resources/planner-overview.md

@@ -35,7 +35,7 @@ GET /groups/{group-id}/planner/plans
 
 When you [create a new plan](../api/planner-post-plans.md), set the **container** property on a plan object to make a group its container. Plans must be contained by a supported resource.
 
->**Note:** The user who is creating the plan must be a member of the group that will contain the plan. When you create a new group by using [Create group](../api/group-post-groups.md), you are not added to the group as a member. After the group is created, add yourself as a member by using [group post members](../api/group-post-members.md).
+>**Note:** The user who creates the plan must be a member of the group that contains the plan. When you create a new group by using [Create group](../api/group-post-groups.md), you aren't added to the group as a member. After the group is created, add yourself as a member by using [group post members](../api/group-post-members.md).
 
 
 ### Container type: User
@@ -65,11 +65,11 @@ Alternatively, you can specify the URL for a user.
 
 Users can upgrade their personal plans into group-based plans by [moving](../api/plannerplan-movetocontainer.md) the plan from the user container to a group container, changing the type of the container for the plan from `user` to `group`. 
 
-### Container type: Teams Channel
+### Container type: Teams channel
 
-The Teams channel container type supports plans created in Teams shared channels, where the channel is the container for the plan. Plans that are pinned in the shared channels would be deleted when the channel is deleted.
+The Teams channel container type supports plans created in Teams shared channels, where the channel is the container for the plan. Plans that are pinned in shared channels are deleted when the channel is deleted.
 
-To [create a new plan](../api/planner-post-plans.md) in a Teams channel's container, set the **container** property on a [plan](plannerplan.md) object with **type** being `teamsChannel`, and the id should be formatted at "{team-id}/channels/{channel-id}
+To [create a new plan](../api/planner-post-plans.md) in the container of a Teams channel, set the **container** property on a [plan](plannerplan.md) object with **type** as `teamsChannel`, and the ID should be formatted as "{team-id}/channels/{channel-id}".
 
 ```json
 {