Install Tor Browser from the right place, verify it, set the security level, save the addresses, set up the account and sign in for the first time.
nexusb2l7fmqnefwphyy7m5zjhlkytlbo7qbb5lu5dlczr3azgii2gyd.onionnexusma2iqgauqqvjcgds4ckv5xbf272tkfagq4epojjhsgleqpwxiqd.onionnexusabcd6tyfhdwilyitaqiri6tisj2v2hueyjuj6qkvd6azvi5tuqd.onionSix things done once, in this order. Together they take about forty minutes and they are the difference between a setup that holds and one that only feels like it does.
Each step assumes the one before it. Verifying a download you got from the wrong place proves nothing useful. Setting a security level in a browser that was modified before you installed it protects nothing. Saving addresses is only worth doing if you can trust the browser you save them in. Work down the list rather than picking the interesting ones.
A paid privacy service, an extension, a cleaner, or anything that promises to make Tor faster. None of those help and several actively hurt. If a step here seems too plain to be the real answer, that is because the real answer usually is plain.
Where to get Tor Browser, why the source matters more than the version, and the mistakes that put a modified copy on a machine.
The signature check that proves the file came from the Tor Project unmodified, why it is worth the ten minutes, and what a failure means.
Tor Browser ships on its most permissive setting. What the three levels change, why Safest is the right default here, and what breaks.
Nearly every phishing story starts with somebody looking for an address during an outage. Saving them properly is the cheapest defence there is.
Username, password, recovery phrase and two factor. Ten minutes at the start that decide what a leak elsewhere costs you later.
What to do in what order the first time you open a Nexus address, including the one check that has to happen before you type anything.