>>4673325
Oh. It's simple enough. In fact, you're already doing it.
Well, it may depend on a device, but I'll try to be general. First, you navigate to the thread you want to reply to, or to the index page if you want to create a new thread. Then, you fill in the fields. Captcha is required on most boards, and you need a file to make a new thread everywhere but in /d/. Also, I don't know weather it is possible to send an empty message. Never really got around to try it out. Also, don't forget to leave the spam trap empty. Lastly, you click the "Submit" button.
There you have it, you have posted on iichan.hk! You did not mix up the address in the process, did you? Some of the board links actually lead to different resources, so you need to be careful.
Also, if I were you, I'd follow the board guidelines under the post form. And just the general stream of conversation. If something is not discussed, it may be a hint that it is not welcome here. Especially if it is a polarizing topic, or a generally nasty one. Generally don't expect getting away with posting NSFW either.
That's about it, I believe.
Faithfully yours,
Captain Obvious