In Grid view, there are two ways to open a work item mode for editing:
In List view, you have to click on sidebar icon to open a work item.
There are two types of work items in system. Ones that are synced from Jira and ones created by users manually.
You cannot change the "Name" and "Description" of synced work items since they are synced with Jira. To change them, update the fields in Jira.
The phase can only be updated according to the qTest Pulse workflow. Details on the flow can be found here.
For information on adding test cases, see the Creating Test Cases article.