Once you have your account structure setup in SAP BTP Cockpit, navigate to Global-account → Sub-account → Space. Afterwards click on SAP HANA Cloud from the menu on the left side of the screen.
For the candidate SAP HANA Cloud instance, navigate to Actions → Open in SAP HANA Cloud Central.
A new tab will be opened for SAP HANA Cloud Central Cockpit and your list of instances will be displayed for a selected space. From Actions column, click on the 3 dotted icon.
Select Start or Stop as per your need.
Only for stopping of HANA instance ,it will prompt a reconfirmation and once you click the Stop button, your instance will be stopped.