The pcd is 5×108, the pcd is if you imagine a circle which goes through the centre of each bolt, 108 would be that circles diameter and the 5 means 5 bolts/studs. A lot of vauxhalls are 4x100 as they only have 4 studs and them studs are closer as the imaginary circle is only 100mm.
I'm not sure on the spigot diameter, that is important as the nuts and bolts/studs only hold the wheel to the hub, all the force from the road would shear them off with speed bumps and potholes, the wheel needs to be snug over the spigot as that will be strong so the force is transferred to the hub through that.
I'm not sure about the offset either, that is the distance from where the wheel mounts to the hub to the centre of the wheel eg if a wheel is 8" wide and has an offset of 0 then the mounting face is in the centre (4" either side). Spacers will alter the offset though, if you use spacers make sure that you use bolts which are at least the width of the spacer longer than the original bolts.
It can sound complicated but read up on it, once you understand it all you'll see it is quite simple.
