This question should probably be posted in the "Help" section.
Anyway, if you are making a platformer you should go through the platform related (Platform School and Crazie Robbies) tutorials and that will show you everything you need to know. Both show how to animate a sprite.
http://sourceforge.net/apps/mediawiki/c ... =Tutorials
Also, trying a google site search on "www.scirra.com" for "animate sprite" pulls up some useful references. http://www.google.com/sitesearch/