You can add new Route Tables or edit an existing one in your VPC by following these steps:
Go to the Route Tables tab, select Cloud Account and Region and click on Create Route Tables.
Select your desired VPC and select a Route for it. In order to create a route, click New Route.
Enter an IPv4 CIDR Block Address and select the Resource Type. Click Add to proceed with the Associations within your Route Table.
To create an Association, click New Association. Select the Resource Type and the specific Resource. Click Add, set a unique Tag for your Route Table and then click Create.