I would like to create an entity in my datastore from the admin console on google app engine.
To do this, I read I must clicked on the tab \"create\" in the datastor
App Engine will only let you create new entities for a Kind that has already been defined. If you haven't ever saved anything to the datastore, your datastore is a blank slate, and you won't be able to query or create in it.
If you don't want to deploy code in order to write your first entities to the datastore, you can enable the interactive console in production, and write code that generates a model, populates, and saves it. Once you've done that, your Create link should appear.
Check the permissions section maybe you only have the Viewer role which doesn't allow you to create entities.
BTW, the create link looks like this: