Welcome to the RXP Gold Assistant’s Guide to Heavy Netherweave Bandage.
You can buy the manual for this bandage with Burko at the Temple of Telhamat if you are Alliance
Or with Aresella at the Falcon Watch if you are Horde.
And note that the main profit for this guide is to sell those bandages at the auction house.
But if the price of Netherweave Cloth is below 15s at the AH, you can also have a profit selling them for NPCs.