Cannot Find API list Need to Create Channel

Hi

first post is one that is vexing me terribly,

We have just installed Matter most on our systems and are looking at integrating it across board,

as a result we are building our own API implementation to do what is needed
,

the problem I’m facing is I cannot find a list of API commands and requirements.

I have tried to get a list from
//MyURL/api/v3/
//MyURL/api/v2/
//MyURL/api/v1/
//MyURL/api/

among many other stabs in the dark
after some hunting I found a partial guide in the code:
//github.com/mattermost/platform/tree/master/api

which when testing some of the results work others not so much because I can’t seem to determine what the required inputs are

Eg for login need email, team and password and run a GET that returns the my user details

So if anyone can show me where to look for the API’s and what is required in the payloads it would be super beneficial

Edit:

My main concern here is how to use the API to create a channel, and move team members into it
If any one can let me know the URL and the Payloads to post to make this happen I would be truly grateful

Thanks in advance

So for anyone else looking I found the Channel Creation:

Post method
Authorization:Bearer yourToken
URL:http://"+HOST+"/api/v3/teams/“TEAM_ID+”/channels/create

Payload:
“display_name”,“displayName”,
“name”,“name”, (lower case)
“team_id”,“TEAM_ID”,
“purpose”,“description”,
“type”,“O”, (O - Open)