Animating models with frames is IMHO the wrong way to work, if you have a long animation you should load a huge amount of data.
The usual ways are mainly 2 : keyframes over mesh and keyframes over bones.
In an easy explaining of 'em :
U fix a “starting pose” a “middle pose” and an “ending pose”, then u interpolate vertex data between various poses, depending on time, anim speed and wathever u want.
Bones are… bones, wich have vertex linked to every bone (for example upper harm) and bones are linked together (bones from the upper harm and lower harm for example)
When you move bones, that usually moves around the links you move also the vertexes linked to the bones.