How can i create the master customer data

Hi friends,

I have one requirement here, I have to create one master database(MDM) start from very scratch on wards.

My question was

1. How can I do start with this.

2. What are all the software requirement

3. Are there any examples (video's are there).

4.  One customer can have multiple email addresses. One customer can have multiple company. How shall I start with building the Master Customer list in this case?

Please send u r valuable suggestions.