Best way to setup a form with subform for multiple entries

Hi All, I am hoping I get get some help on this one as this one problem is stopping me from progressing with my database. I have asked other questions and viewed tutorials but still have not been able to progress. Therefore I thought I would try again but with a clearer definition of my requirement.

I require a form (with or without subforms) to allow the entry of details received from a customer enquiry.
The customer with send in an enquiry with a reference (CustRef). The enquiry will consist of PartNumbers.
Each PartNumber will have its own PartRef.

So when adding a new CustRef I could be adding several PartNumbers on the same form.
Each PartNumber would need to have its own Primary Key to be auto created at time of entry.
I believe the PartRef would also need to have its own Primary Key?

I have attached a simple sheet showing roughly what I need to achieve.
The PartNumber is the main factor in this database. I already have a PartNumber Table which uses PartNumberID as a Primary Key. I am unsure which new table I need to allow the above. I think I need CustRef and PartRef but not been able to make it happen in a single user friendly form.

I really appreciate any help here as struggling badly despite checking out other posts and example.
I have actually had to put this to one side for a number of weeks as I was not progressing.

thanks again.CustRefForm.ods

@MaaX You have done this before - cross posted without reference - Multiple Entries = Multiple Tables/Subforms?.

You are asking people to research for you what may already be solved somewhere else! It is better to only do this if your original post gets no response and then NOTE that it is cross posted! When solved update each!

Nothing more to be done here.

Hi, perhaps I have made a silly error here, I thought I had posted this in two different forums, therefore two different audiences?

@MaaX The error was not mentioning the cross post and referencing it. It is possibly two different audiences but many work both forums. Read my first comment again!