Instructions for skeletal animation and skinning.

Hi guys,

I got some progress on renderring skeletal animation exported from blender. But still cannot get the point I need. I have attached the Collada file that I used. Please someone give me some hints about how can I manually programme a skeletal animation which seems like the one in this file. I have read the skinning part of the specificaiton. But still feel confused about how can I achieve the effect using Colldada DOM. When I change the inverse bind matrix of a joint,the bone was not changed but the corresponding meshes was.When I change the local to world matrix the joint was moved if the update local to word matrix is disabled. I think I am still outside the door.
Could somebody give such instructions of what steps that I need to do or where I need to look at.
For example, if I have two joint A and B, A is Child of B.If I want to have a skeletal animation to rotate B(and the vertices it inflenced) 45degree with respect to Z axis and then rotate A 30degree with respect to Z axis. Which steps do I need to take. Some pseudocode for this would be great as well.
With many thanks in advance.