Kaltura Session string (KS) is an authentication key and it is required in order to make requests to the Kaltura API. The KS is used to identify the account on which the action would be performed.
You will usually need to specify the KS for making requests to the Kaltura API, either via your code or when using the test console.
There are some requests that don’t require a KS, like Session->start action and other public or pre authentication actions.
You can always generate the Kaltura session (KS) via the API, as described here at the Kaltura help forum. But what if you need to get the KS instantly, without writing any code? For example, you are using the test console and trying to create an entry. You need to specify the KS, but where do you get it from?