In standard situation update can be started by clicking on message box appeared after S32DS Launch:
If you don't see such message - you can check for updates/update your S32DS Installation manually. On main menu bar click on Help -> S32DS Extensions and Updates
Select from available items, then click "Install/Update" button
Download update package from Updated/Patches (for S32DS 3.x - S32 Design Studio | NXP , for ARM S32DS - S32 Design Studio IDE for Arm® based MCUs|NXP, for Power Architecture S32DS - S32 Design Studio IDE for Power Architecture based MCUs | NXP ).
Click on Help -> S32DS Extensions and Updates and choose Go to Preferences.
Click Archive... and locate the zip file you downloaded and click OK
Select the packages and updates then start the installation with the Install/Update button.