i got one!
When you signup, there's a walk-through. You'll end up with an email-like address (eg. example@getalby.com), then you can post that to nostr, and other social media. To turn your lightning into fiat, you can purchase a visa debit card from nostr:nprofile1qqsr4uv8hlsqjgxcwp52d0xll3y0fvjp68vzt9xd89g3ngcgjyzpv4qpzamhxue69uhhyetvv9ujumn0wd68ytnzv9hxgtcvyxz2m or https://bitrefill.com or use #asknostr with your question, and users'll give you help.