Animations animations animations!

hi all,
ive had trouble with this topic for AGES, im looking for either some source code or a tute plz, ive tried “marzs animation tute” but it neva has worked for me.ive tried tutes at all the resources in these forumns but i can neva get it to play.
all i want to do is when i use tthis type of code.

if(key.isDown(key.LEFT))
player move blah blah
and then play the “left” walk animations NONSTOP

even if i hold the left key down hero will move and animate accordingly.

ive seen some VERY complex ways of doing this but im a newb so i only understodd a 10th of the code. im looking for something very simple.

cheers,