Convert my crm to SAAS CRM , do necessary change , configure, setup and deploying on AWS

Hello,

We have our own CRM develop as normal CRM just as stander way like for single client to use and we hosted on particular domain and single domain and its working fine.

Now we want to convert it as SAAS CRM. and deploy on AWS so user can direct subscribe online and start using by subdomain.crm.com
Also we want keep every our tenant database separate.

So I think we use the SAAS concept as - Single code and multi database per tenant basis.

Please write detail in your proposal.
1, What are the change will required to do with the current traditional crm so make it work like as SAAS.
2, What are stuffs you required and how you going to deploy on AWS.

Please answer in very details point wise in one response. As This is serious project so i do not want to talk with person who have no idea and just talking bla, bla..

Thanks!