Sort orders a stream by one or more fields. Set the first key and then add a second key to decide ties. A descending amount sort places the largest amount first, but two records with the same amount still need another key if the order matters to a later step. Always check the incoming order before using a tool whose meaning depends on it.
Sample selects records by a configured method. First N and Last N refer to incoming positions. The 1 of Every N Rows method keeps the first row in each block of N incoming records rather than the highest value in a business group. A percentage sample also depends on the number of incoming records. Sampling before sorting can answer a different question from sorting before sampling. Keep the method and its number visible in Configuration when you explain your result.