Welcome to nostr! You can get started by following others and/or hashtags to define your own feed.
You can modify your profile with as much or as little info as you want. A nostr address (sometimes labeled as nip05) can help pin your nostr public key to a domain or organization that will attest that a given username correlates to it for some verifiability. A lightning address (or lud16) can be set if you have a lightning wallet with a provider like strike, lightning tip bot, getalby and others. It can let others send value to you like tips for posts.
check out various applications that integrate nostr where you can login such as...
Zap.Cooking - recipes by fellow users of nostr, straight to the point without superfluous stories or ads.
Zap.Stream - watch live streams
Corny.Chat - live audio spaces with customized rooms and scheduling.
For websites like the above, it is recommended to use a nostr extension that supports logins such as getalby or nos2x.
If you have questions, be sure to add the hashtag #asknostr to your post.