Hi, @Anjalipurushothaman ,
I see that S32K3 SDK is unavailable in from the Add update side. We will fix this shortly.
Till it is available, you can get the S32K3 SDK by following these steps:
1. Select "Help", then "Install New Software "

2. Then from the opened window, for "Work with" option - select the RTD from the drop down menu,

3. Then select the S32 Design Studio S32K3 SDK

Then you can install the S32K3 SDK.
We will also work to fix the issue and make it available on S32DS Extension and Updates
Thank you. Best regards.
- Mehul Patel