when did chauvlin and his men break into the hut? what did they find?

What chapter are you referring to?

At late night when everybody were sleeping and Sir Andrew and Lord Anthony were taking about something very secretive Chauvelin’s men broke into the inn.On searching they(chauvlein and his men) found out some scraps of paper one with a small red flower design and another written by Andrew St. Just.

Chauvelin and his men break into the hut when the wife of sir percy blakeney shouted to her brother that he should save the life of his leader by firing them. They found that the hut was empty and a note was there, in which instructions were given on how to escape from the hut