"After she went."
Translation:Ar ôl iddi hi fynd.
mynd is the verbal noun, which is similar to the infinitive in some ways - so it's neither present nor past nor future, necessarily.
In dw i'n mynd, for example, it's "I am going" (present continuous); in dw i wedi mynd, it's "I have gone" (present perfect). The mynd itself does not show the tense. (And fynd is just a mutated form of mynd.)