I 've tried to do it from here...
FRDM-K28F|Development Board|Kinetis K27/K28|NXP
But when I click on download button under
"Click below to download a pre-configured SDK release for the FRDM-K28F"
I get to the main nxp.com page.
When I download a complete SDK 2.0 or 1.3 for Kinetis I haven't this board in a list of boards.
How I can get this SDK?
Maybe your account is inactivie, please refer to the below link for how to solve this.
I hope it helps