Once installed, click on "Recent" in the menubar to access your recently viewed contacts, activities, contributions, etc.
Screenshot (click to enlarge)
Releases
Since CiviCRM 5.x, extension releases compatible with CiviCRM 5.0 are compatible with 5.0 and later. An extension release compatible with 5.25, for example, means that it requires CiviCRM 5.25 or later.