Where i find "functions" that i can use?

[BattleSheep94]

Where i find these functions like.

   message.CreateReaction(Client, ":sad:");

or
server.Broadcast($"Discord Message: {message.author.username} - {message.content}");
Sorry if this is not called functions my english is not the best
The examples are not the best but i dont search a hook. i mean something like:
PrintToChat("[DISCORD] " + message.author.username + ": " + message.content);
But not to chat rather to cmd. I try to run a rcon command if a discord message is incoming.
And i dont know how to run these command.

Another thing is how i can give someone a role in discord.
Like if someone type a message ingame the user in discord get another role.
e.x. from "Player" to "Member"