How I can use
scratch-def.json for creating new org without using DX CLI?
Go to "Manage Connections" from the IC toolbar (it's a on the drop-down that says "Open Connection"). Click on the DX Icon in the top-left to start creating a scratch org.
On the new scratch org dialog, there's a folder icon next to the field for Org Name. You can use that to pick an existing
scratch-def.json. The the dialog will be populated with the setting from that file.
This is particularly useful when your scratch org has expired on an existing project.