Click library, tool, and find "The divinity engine 2" Download that. Do find some tutorials and such to get going or join the forum and discord to get help. The DE edition was release yesterday, so there are some issues atm (from Discord):

"For those who were very fast, there was a short period where the editor would point to the wrong Data folder and crash. This is fixed now, but if you were one of the early birds and your editor crashes on startup with a splash screen "Starting Services". Please do the following to fix this:

Find the file Steam\SteamApps\common\The Divinity Engine 2\DefEd\Config\config.xml

Edit the <DataPath> element:
Before:
<DataPath>G:\Games\Steam\SteamApps\common\Divinity Original Sin 2\Data</DataPath>

After:
<DataPath>G:\Games\Steam\SteamApps\common\Divinity Original Sin 2\DefEd\Data</DataPath>"

Happy modding!

which editor do i use to make my own mods into editor????