The Holy Spirit guides and shows but he also speaks to us.  The Holy Spirit will always speak what He hears.  He is the Spirit of Truth.

What happened to Philip is Acts 8:29 is a good example of the Holy Spirit speaking.  Philip saw a chariot with an Ethiopian Eunuch sitting in it and then the Holy Spirit spoke to him.

Acts 8:29 Then the Spirit said unto Philip, Go near, and join thyself to this chariot. KJV

In this incident with Philip, notice the Holy Spirit spoke to Philip and told him what to do, “Join thyself to this chariot.”