Initial install:

curl -sSL https://get.docker.com | sh
sudo usermod -aG docker pi
sudo reboot
sudo docker run --restart always --name=portainer -d -p 9443:9443 -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce:linux-arm64

Open your browser to your pi instance ip address via https and add the :9433 to it for the port.
Login as admin and set your password.

Upgrade instructions:

sudo docker stop portainer
sudo docker rm portainer
sudo docker image rm portainer/portainer-ce:linux-arm64
sudo docker pull portainer/portainer-ce:linux-arm64
sudo docker run --restart always --name=portainer -d -p 9443:9443 -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce:linux-arm64