On the top left of cheat engine, right under 'File' should be a blinking icon, click on it and select the game. Then decide on whatever you want to increase/decrease, in this example I'll use Leg-Str. Put in the value of that where it says 'Value:', then click 'First Scan', then change the Leg-Str value by either leveling up or kicking enemies. When Leg-Str changes, re-type the new value and click 'Second Scan'. Keep doing 'Second Scan' until you only have 1 or 2 addresses left. Then you can double click it and change the value as you like.
Also make sure your 'Value Type' is '4 Bytes', although for me it's automatically set to that.