Follow the documentation and create namespaces for objects in your deployment as you need them.
To enable the default seccomp profile, use the reserved value /runtime/default that will make sure that the pod uses the default policy available on the host.
Follow the Kubernetes documentation and apply security contexts to your pods. For a suggested list of security contexts, you may refer to the CIS Security Benchmark for Docker Containers.
Ensure that namespaces are created to allow for appropriate segregation of Kubernetes resources and that all new resources are created in a specific namespace.