Hi @Dipen
document your existing pfsense configuration ie firewall rules, vpns.
Claim your Meraki device in the dashboard and start building out your config
MX install guides:
https://documentation.meraki.com/MX/MX_Installation_Guides
Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/
I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.