I'm on my phone atm so I'll keep this short.
This section of the site is for approved analyses to be worked on. If you'd like to write an analysis, you can reserve one
here and a moderator may approve your request. Example sets such as the Magikarp one you provided should be posted either in the PS! LC chat room or in the appropriate thread in the LC subforum under Competitive Discussion. However, Magikarp is unfortunately outclassed in almost every regard by other Water-types in the metagame so I'm not sure it'd even be worth discussing in those places either.
If you have any questions about anything at all, feel free to reach out to me via Smogon conversation, PS! private message, or by posting on my profile. Stick around in LC!