Soft cups question

An
So I might try soft cups next month.
I have a couple of questions (might be silly) but Im new with this.
When do you put the soft cups? 
Is it right after sex (before getting up?)
Or after sex, but you can still pee?
My dr. Told me that you should pee after sex to decrease chances of getting a UTI.. But not sure if that interferes with the soft cup usage lol. 
And then, how long do you keep it inside?? 
Any feedback is appreciated =)