Hey, if your that early in your ae usage you may not understand that most of the blood effects you see are included in plugins. The one i use is Action movie essentials from andrew kramer over at videocopilot.com also just a peice of advice watch most his tutorials even if you dont need those particular effects, i found it as a really great way to learn ae and most of the basics and youll find yourself having ideas on how to create your own effects.