With this phrase, Samuel is encouraging Saul to act and do what he thinks is best for the Lord and his people.1 Quite possibly Samuel has a military action in mind given the earlier reference to the Philistine outpost (1 Samuel 10:5),2 in which case he expects Saul to take the initiative and set Israel free from Philistine control.3
7 Now when these signs meet you, do what your hand finds to do, for God is with you.