How do i enter my business expenses ie supplies and materials purchased

I have a Bath & Body Care company that makes soaps, lotions etc.  I have to CARRY an INVENTORY of all my oils, butters, packagings, labels etc in order to run my business.  This can be quite expensive so I need to show this expense when purchased for the year even if it wasn't used to make a sold product yet. 

1. What is COST OF PURCHASES mean vs. MATERIAL & SUPPLIES on the Cost of your goods section? 

2. Where do I enter material & supplies purchased for the year regardless if it was used in a product and sold?  

3. Do I show the value used to make the product I sold on the MATERIALS & SUPPLIES line? But if so where does the unused get entered (?2)?

4. Inventory value is an asset (+value) don’t I have to show how my inventory increased?  If so where does the unsold material & supplies that I purchased for the year get imputed as an expense?

5. The line that says: OTHER COSTS TO PREPARE FOR SALES is this where the postage etc gets entered regarding the sale to ship it to the customer?  

I was going to enter all postage expenses under OTHER BUSINESS EXPENSE but I am now curious if the postage for SOLD items should be entered under the Cost of your goods section?

Thanks so much for your time!