I am planning to do POC to implement faas server less architecture
Any best practices to follow while implementing this architecture and how actually to achieve it?
Functions are generally short lived and stateless (although stateful are also possible etc Azure Durable Functions). They are perfect to handle spikes. I would advise use any existing cloud serverless services like Azure Functions , Aws lambda.
If you don't want to use existing serverless offerings by cloud providers, You can also write and deploy your own serverless functions in your preferred environment using containers and kubernetes using framework like OpenFAAS https://github.com/openfaas/faas
Make sure you know the pros and cons before you actually want to go for this approach.