ArangoDB won't run on MicroK8s
The prerequisite for ArangoDB binary requires a CPU supporting SSE4.2.
You can install ArangoDB on a MicroK8s cluster with a Helm.
microk8s.enable helm - Using Helm within Microk8s allows you to manage, update, share and rollback Kubernetes applications.
Here you can find a manual showing how to use the ArangoDB Kubernetes Operator with Helm.
Also, for the general guide I recommend this thread.
I hope it helps.