Opening the market
Everything below assumes you start from nothing. If you already run the Tor Browser, skip to the address bar.
Step one: the browser
Download the Tor Browser from torproject.org. That domain is the only source. Builds offered by app stores, tech blogs, and comment sections are how people end up with instrumented browsers that report everything they visit. Check that URL before you download, the same way you will check the address bar later.
Step two: the circuit
When the browser opens, it builds a circuit: three relays standing between you and the rest of the network. The first load is slow by design, and a .onion connection adds its own hops on top. Give it a minute or two before you decide anything is broken.
Step three: the address
Copy one of the three strings from the block above. Paste it into the address bar and press enter. Do not type it. Sixty-two characters by hand is how typos are born, and the addresses page covers what a typo does to you.
Step four: the check
When the market's page appears, look at the address bar. The full string you pasted should still be sitting there. If it is, you are in. If the bar shows anything else, close the tab and copy again.
What a wrong load looks like
Most wrong addresses never load at all. You get a spinning icon and a connection error, which is boring and safe. The interesting case is a wrong address that does load: a parked page, a clone of the market, a login form built to be convincing. A clone cannot change the address bar. Read the bar.
Three things that should make you close the tab: a page asking for your market password before you have logged in anywhere, a credentials form on a clearnet domain, and a verification step that opens a second window on its own.
It stalls
Stalls happen. If your Anubis Market Tor connection hangs, reload. If it hangs again, ask the Tor Browser for a new circuit, the reload control in the address bar, and try once more. Then move to the second address, then the third. Three stalls in a row across three different strings is a problem with your route, not with the market, and the troubleshooting page starts there.