Question about Dquartets

[CrawlingSponge]

HELLO, thanks for your convinient tool, i hava some questions when i perform the Dsuite.

1. i use the Dsuite Dquartets to get the all possible quaitets, but only with the limited ones, also the species should be the outgroup appeared at the inner branch?
2. another questions about the results: if i wanna prove the branch did not have introgression in the history, P value logically should be very large one and that also means the intrgression is not significant. am i right?

hope for your reply! thanks very much.

yours, Yuan