Inventory Procedure

Good day , I have several question on the correct way to register on inventory.
Thinking I already imported and inventory with a bath, I would like to know the correct way to deduct or increase inventory items.
1- Are the Incoming Items register with a buying invoice, or goods receive?
2- How should be deducted items from inventory , with a sales invoice , or production order ? is it posible to deduct items from inventory with Inventory Kits.
We make seat covers and use several materials to make a seat cover, one of my problems are fabric color because I must make 1 inventory kit for each color by each item.

What does this mean?

If the Goods Receipts tab is not enabled, goods are automatically added to inventory by either a purchase invoice or payment form that includes them. If Goods Receipts tab is enabled, you must enter a goods receipt if the option to track receipt of goods is selected in the inventory item definition. They can also be added as finished items in a production order.

Inventory items are removed by sales invoices or receipts that include them, or by production orders that include them in the bill of materials. Delivery notes are similar to goods receipts, but in reverse.

Only when the inventory kit is sold. Inventory kits are for items that are stocked and counted separately but sold together sometimes.

There are Guides about all of these questions. Please read them.

What does this mean?
What I meant is I already have an inventory in manager program, added with a batch create.