You need to perform this operation twice. Add one route entry directing to the VPC and add one route entry directing to the on-premises IDC, so that the on-premises IDC can communicate with the VPC through the VBR.
Log on to the Express Connect console.
In the left-side navigation pane, select Virtual Border Router.
Select the target VBR in the VBR list.
In the page of VBR details, click Add Route Entry.
In the displayed dialog box, enter the following information:
Destination CIDR Block: The CIDR block cannot include any public IP.
Next Hop Direction: To forward data to VPC, select To VPC. To forward data to IDC, select Leased Line.
Next Hop: To forward data to VPC, select the data exit on the VBR, namely, a router interface of the VBR.