OK here's what you do: (don't know how to compile half-life 2 models tho :x)
Import Vegeta's main .smd, the reference (usually named vegeta.smd)
On the upper right corner, go to JOINTS tab and delete Bip01.
Now, import any css model reference, but this time uncheck TRIANGLES when you're prompted.
Scale vegeta in X, Y, Z,
and U (U makes it so that you scale it proportionally without somewhat "deforming" the model - making it skinnier or fatter).
select one of vegeta's arms and then go to the Model tab in the upper right corner and click on rotate (Default hotkey: F3) Start rotating it until it goes horizontal then hit F2 (Hotkey for Move button). Move it around so that it would be attached to the shoulder again.
Do the same with the other arm.
WARNING: DO NOT rotate or move ANY of the bones, it will make your model look like crap once you compile it.
Now, as for assigning, go to the joints tab and everytime you want to select a model's part just hit F1 (BUT BEFORE MAKE SURE THAT THE OPTIONS OF "SELECT" HAVE THE "Vertex" BUTTON PRESSED, WHICH YOU CAN FIND BELOW ALL THE BUTTONS, IN THE RIGHT MIDDLE MORE OR LESS, BECAUSE IF YOU SELECT FACES, THE MODEL WILL LOOK LIKE CRAP ONCE YOU COMPILE IT.)
Check the Joints list out and see what's what. Check out Arm, Elbow, Knee, Leg... (u select the joints simply by clicking on them).
Click on any of the joints and then hit F1 and select the limb (again, the VERTICES, NOT THE FACES) you want to assign to that bone. This is done so that the model would know what is his arm, leg, etc. Go to the joints button and click on assign. If you select the bone once more from the list, u'll just lose the vertex (limb) selection u made and have to select all over again. If that happens, hold ctrl and hit z (undo). That's why you have to select the desired joint and then the vertices.
Once you think you're done, click on Sel UnAssigned (SELECT unassigned) to check if you missed anything out. Once EVERYTHING is assigned, click on the ANIM button at the bottom right corner and then import an animation .smd file(sequence .smd) over it. When you're prompted, just click on NO. You don't need to import the animation after the 30 frames your model stands still.
Play the animation and see if it looks good to you. Now, export the whole smd as REFERENCE, rewriting your CSS reference smd (although I suggest you rename that original file first, just in case).
Now all you need to find out is how to compile...
Sorry, that's all I can do for you.
:EDIT:
OH crap almost forgot. Before u ever learn to compile, MAKE SURE THAT VEGETA'S TEXTURES (.bmp files in vegeta's folder) ARE IN THE CSS MODEL FOLDER!