Dealing with HD, Walmart, Lowes, etc.., requires deep pockets. Margin purchasing, consignment sale, guaranteed sale ventures, long payment schedules, all require a big credit line on your part.
Your computer system must be compatable to, and work with, their purchasing systems. With Lowes and Walmart you must be able to distribute chain wide within 7 days of go date (especially for an ad).
HD has their system broken into purchasing districts. You must introduce yourself, and befriend, each district purchaser for the relevant dept you want to sell to. Once you have enough of them on your side, you can then seek head office approval to carry your product as an approved vendor.