These tutorials are most effective when used in conjunction with the editing software. Ideally, you should watch a tutorial then use the editing software to practice the techniques. Watch and practice again and again, as much as you need. Do not use these tutorials as an excuse to miss class. They are not a substitute for actual classroom learning, but simply an extra tool to help you refresh your skills and explore new techniques.
Basic Trimming with the Ripple Edit and Rolling Edit tools
Trim mode using right and left arrow keys
Dynamic Trimming with J-K-L keys
Dynamic Trimming on audio tracks