As a newcommer, your first reflex should really be to check out the manual first when you have trouble. (Or clicking the Help links within C2).
In this article you can read:
Speed The number of animation frames shown per second. For example, if set to 5, each animation frame lasts for 1/5th of a second. Set to 0 if you do not want the animation to play (e.g. if a tile set is used with a different tile in each frame).
Which means, the closer you get to 0, the slower your animation plays.
And also you don't need to set it from events at runtime, you can very well define this property once and for all in the animation editor/properties bar.
Also, any graphic editors can allow you to make 8-bit sprites. Nice sprites come from the efforts and skill you put in them, whatever tool you use.
Common recommanded graphic editors are graphic gale, paint.net, gimp and photoshop.