Ok as you can see i've started my vehicle package VH_CWE_Jetbike by importing 3 textures, 1 skeliton mesh(vehicle), anim 1 anim set. These i've set up as normal in the sub-folders
To create a new Physics Asset we need to select the vehicle mesh and right click, from the list select Create New Physics Asset
by clicking yes each time we end up at this screen which has already made us a simple collision box for our mesh
ok hear we now need a physics material, so in your material secton right click and add a new physics material give it a name.
now click the blue arrow on the PhysicsMaterialProperty line which gives its name automatically and then in MaterialType write Metal. I don't know why but the Manta has it so we'll have it as well. And gets entered Here
Next we add a collision box (yellow arrow) and with the scale tool (red arrow) we scale the box up (gizmo center of the box) you can also move/rotate the boxes via move or rotate tools, remember to hold the mouse over the gizmo to get this to work.
Hopefully thats all we need in this section, if i find more i'll come back and add to it.