1.1 They said "Make two wallets and go straight to market"
1.2 They called these initial wallets "A" and "B".
1.3 Wallet "A" was made in the clear using legit credentials and was considered the Primary or permanent wallet. Wallet "B", the Secondary, was created in the dark using doctored information provided from behind a "plasmashield" (as opposed to a firewall) [1]
1.4 "A" never touched the dark, and "B" never touched the clear
1.5 Bits were purchased in the clear and went straight into "A".
1.6 From "A", bits were transferred straight to "B".
1.7 "B" was then accessed from behind the plasmashield and was used to top up a temporal DNM account to make payments.
1.8 When more bits were needed, a new wallet would be invoked in the dark (wallet C, D, E, F...etc)
1.9 Wallet "A" would then be used in the clear to top up wallet "C".
2.0 "C" would then be accessed in the dark and used to buy stuff at market X.
This cycle repeated itself over and over.
[1] Plasmashield: behind the protection of VPN, TAILS, 128+bit Passwords, Encrypted password storage that only requires the recall of a single pasword, the proper use of PGP/GPG, and whatever other obfuscation is thought or felt to be necessary.
I'll break it down a bit more clearly:
If you are a buyer, generally speaking tumbling is a waste of time and money. UNLESS you're purchasing your coin directly via a service like Coinbase that's tied directly to your bank account and it's actually your bank account. Then it is elevated to "prudent". Maybe look into other ways of getting coin if you're planning a large purchase.
Now with that said, if the cost is something you're comfortable paying and you choose to do so for "peace of mind", totally fine. I'm not gonna knock you for that, it's your choice to make.
/u/Vendor_BBMC has a nice way of elucidating this in quite a few of his posts, for example.
If you're a vendor, you aren't purchasing coin to make purchases on marketplaces hopefully (because why not just use already obscured coin from your income pre-tumbled, of course transferring it to an established buyer account beforehand so as not to stick out like a sore thumb) so this framing is a bit null in and of itself.
Tumbling is a key piece of laundering money. You don't launder money into drugs. You launder it out. Imagine being a super cool ninja type fella who does all these crazy tricks and stealth flourishes while walking a mile to pick up groceries, and then all the way back home as well. Like, cool, but why? It didn't need to be so strenuous. If you just like doing ninja stuff, great, but don't do it and then complain about it. Be aware of the choices you make and that they are indeed choices.
And with that, I retire for the evening.