Blown main fuse

Are you sure you do not have one of the small battery cables hooked up the wrong terminal. You have a direct short to ground somewhere. If you cannot find it try disconnecting the alternator.

That may be the problem. There are two cables that are connected to the negative terminal. The negative cable it the first picture and the positive has four wires coming from it.

I cannot tell where they are all connected. Make sure nothing from the positive side is touching ground.

As WRENCHTECH has suggested, Disconnect the alternator and then connect the battery cable to see if the fuse blows. If it stops blowing then replace the alternator. Do the same thing with the starter and trace positive battery cable to make sure it is not rubbing anywhere.