Hi Gokul,
You can download HANA Studio 70 from Service Marketplace
Go to the below path:
Then select Installation and Upgrades, then select Browse our download catalog then select SAP HANA
Although you can download HANA Studio 68 from below link:
https://hanadeveditionsapicl.hana.ondemand.com/hanadevedition/
Regards,
Vivek