I need a Tech Pack For Fashion And Garment Production

Hello,

I have a leather goods backpack that i'd like to turn into a tech pack for manufacture production
I have already got a sample created from a manufacture but that was from the vauge drawing and measurements that I gave to them to produce me a sample and it came out great but not perfect.

Now im looking to approach this professional with a proper design and proper layed out meaurements for the backpack