Hi,
first thing to do you made just right. Ask here.
Secondly, there are some things you should read through first (guidelines of editing):
https://en.numista.com/catalogue/contributions/instructions.php
And finally, open any country and slide right down - there you will see:
A coin doesn't exist in the catalogue yet? Add it yourself! - this is where you start.
Do not worry with adding something wrongly, I (or referee) can always send the request back to you to do some more modifications to it, it happens as a form of conversation. So feel free to add it!