Integration decision and analysis in ECC to S4 Hana migration

Hello Experts

Our customer is planning to move from ECC to S4 HANA and as an Integration expert I am suppose to provide the inputs on Integration plan and Best Practices.

Can you all please help me with the steps and activities I should perform in order to understand how the new Integration Architecture should look like and what Do's and Dont's I should consider.

This is the first time I have to work on this so any help is very much appreciated.

Best Regards

Neha