Macro to mail merge

Dear experts,

I have a unique requirements and i have been trying to find a solution since hours now but to no success.

I have an excel sheet where i have some data for eg. customer details, and i want to have a button in excel that when clicked will open up my word document and mail merge these fields on the word document.

But i don't know how to do this

I don't want to use the standard mail merge feature. I want a button instead.

All the fields in excel must go into appropriate places in word

can somebody please have a look at these attachments and tel me what VBA code shall fulfill the requirements?