So that... / In order that...
Expresses purpose. Always followed by the subjunctive when the subjects are different. One of the most common subjunctive triggers.
I'm explaining it to you so that you understand it well.
Speak more slowly so that everyone can follow you.
She did it so that nobody would know what had happened.
I explain it to you so that you understand.
Close the door so that the cold doesn't come in.