For actually uploading new packages to the archive you need to be "DD" (Debian Developer), which is a bit more involved process to go through. "DM"s (Debian Maintainer) is easier and can do already lots of things. It's also possible to start out by finding an existing DD that sponsors your upload, i.e. checks your final packaging work and if it looks alright will upload it in your name to the repositories.
You might also check out the wiki of Debian, it's sometimes a bit dated and got lots of info packed in, but can still be valuable if you're willing to work through the outdated bits. E.g.:
https://wiki.debian.org/DebianMentorsFaq
The policy manual serves as both ruleset but also explains lots of things w.r.t. packaging, as that's part of the ruleset: https://www.debian.org/doc/debian-policy/index.html#
For actually uploading new packages to the archive you need to be "DD" (Debian Developer), which is a bit more involved process to go through. "DM"s (Debian Maintainer) is easier and can do already lots of things. It's also possible to start out by finding an existing DD that sponsors your upload, i.e. checks your final packaging work and if it looks alright will upload it in your name to the repositories.
You might also check out the wiki of Debian, it's sometimes a bit dated and got lots of info packed in, but can still be valuable if you're willing to work through the outdated bits. E.g.: https://wiki.debian.org/DebianMentorsFaq