Open the AWS DMS console, and choose Replication instances from the navigation pane.
Choose Create replication instance.
Configure the following parameters: Name - Enter a name. Description - Enter a description. Instance class - Choose the instance class. For more information, see Selecting the right AWS DMS replication instance for your migration. Engine version - Choose your engine version. Allocated storage - AWS DMS doesn't use a significant amount of storage because storage is primarily consumed by log files and cached transactions. For more information about allocated storage, see Allocated storage in the table in Create a replication instance. VPC - Select the virtual private cloud (VPC) that you want the instance to be in. Multi-AZ - Choose Yes or No. For more information, see Working with an AWS DMS replication instance. Publicly accessible - Choose this option if you want the replication instance to be accessible from the internet.
Expand the Advanced security and network configuration section, and then configure the following: Replication subnet group - Select the replication subnet group that you created. Availability Zone - The Amazon Elastic Compute Cloud (Amazon EC2) Availability Zone where the replication instance will be created. VPC security group(s) - Choose a VPC security group that you want to assign to the replication instance to manage the outbound traffic. KMS root key - Choose the encryption key to use to encrypt replication storage and connection information. You can choose the default key with an alias (aws/dms) or a customer managed key (KMS key). For more information, see Setting an encryption key and specifying AWS Key Management Service (AWS KMS) permissions.
Expand the Maintenance section to manage when modification and software updates occur on the replication instance. Auto minor version upgrade - Choose this option to apply minor engine upgrades to the replication instance automatically during the maintenance window. Maintenance window - Choose this option to designate a weekly time range during which system maintenance can occur, in Universal Coordinated Time (UTC).