NOTE: Custom emotes are only available for>=1$ patrons of https://patreon.com/Mirsario 

First you will need to associate your patreon account with your SteamID at http://mirsar.io/Register if you didn't do this yet.
If it's done correctly, then you should see a heart in main menu's top left corner next time you load the mod.
After that - just place .png files in this folder with both dimensions not bigger than 32px
Any directories inside this folder will create new emote pages that you will be able to switch between by scrolling the mouse wheel while holding the emote wheel button.

The host, or any other player, do not need to have your emotes, as they'll be sent automatically.