You must first be of Solider Lord Rank
1. Go to SDGO TW website here
and click the circled icon.
2. You will be in the clan creation page.
Fill out your log in information as you usually do for in game.
3. Please click the top box shown on this picture below
Then click the bottom circled box for accepting the agreement to make a nice clan Blah blah blah.
4. Fill out your clan information
Finally click the bottom box for completion.
You are now done, you have just made a clan.
For how to accept members. How to reject members, How to delete members. I will update later.