Furniture ERP Development

Need to build an ERP for Furniture Company where :

We manage our clients - add, edit, delete
Add projects for clients
Add documents related to project - Quotation, PO
Mark payments due date for the project
Add products sourced for the project or vendors
Add comments for the project and emails related to project should go automatically in there. Should have the option to reply emails from there too.
Add project add-ons or enhancemenet settled - Seperate quotation, PO and payment dates will be added for add-ons
Multiple projects can be added for one client
Total client worth - sum of all the project value settled with client, how much is received and what is pending

Project Flow - I first want to finalise Layout of the project. I want a super easy UI and everything at one place. System architecture is most important. Once finalised, we go with development

I have attached project detail scope, you can check that too.