A beginner on a darknet market has two disadvantages: no history, and no instinct. The history comes with time, and the instinct comes with habits, and the habits are the part you can install on day one. This is the path from zero to a confirmed first order, and the mistakes that are expensive to make.
The path
Install Tor Browser from torproject.org, typing the address yourself. Copy a mirror from the list, paste it, wait for the circuit. Read the address in the bar backwards before you register. Choose a username with no connection to your real identity, a long password you have never used, and turn on two-factor authentication in the first session. Deposit a small amount from a personal wallet, pick a vendor with a real review history, read the listing's delivery window for your region, encrypt the delivery details, and place the order.
That is the whole path, and the step-by-step guide covers each of the first four in more detail.
The mistakes that cost money
The typed address is the big one. A v3 address is 56 characters, and a typed one is a chance for a clone, and the clone is a copy of the market that takes the password and is done. The fix is the copy, and the copy is free.
The large balance is the second. A beginner who deposits a month's supply at once has a month's supply sitting in market-controlled wallets. The fix is the small deposit, sized to the order, with the rest staying in a personal wallet.
The exchange payment is the third. Paying straight from an exchange connects the payment to an identity that the exchange holds. The fix is the personal wallet, one step removed, and the coin choice, because Monero does not leave the trace that Bitcoin does.
The missed timer is the fourth. A dispute opened after the escrow timer ends is a complaint, not a dispute, and the claim has lost its weight. The fix is the habit of watching the timer on every order, and opening the dispute early rather than late.
The habits that cost nothing
Five seconds before every login, the backwards read of the address. A small deposit per order. The delivery details encrypted, every time. The listing's delivery window read before the order, not guessed after. The vendor's review history checked, including the recency, not just the count.
Each one is a small thing, and the small things are the whole game for a beginner, because the beginner has no history to fall back on, and the habits are the substitute for the history. The security basics cover the stack, and the first order guide covers the sequence.