md5link P C T [X Y Z]
This links two models together. Every model you load with md5load has an ID. The first model you load has the ID 0, the second has the ID 1, and so on, those ID's are now used to identify the models and link them together. P the ID of the parent model. C to ID of the child model. T name of the tag that specifies at which vertex the models should be linked. X, Y, and Z are an optional translation for this link.