You need 6 wheel spacers and 1 of everything else. I made mine black so the pictures aren't very helpful but here's a video showing how it assembles (I guess in the video it shows it disassembling
).
It takes:
3 V wheels and 3 M5x40 bolts & nuts
2 T nuts and bolts to hold the tensioners to the rails
1 M5x10 to hold the motor mount to the rail
4 bolts to hold the motor to the mount
2 idler pulleys same as ERC original
1 drive pulley same as ERC original
about 2 meters of belt
1 meter of 20x20 V extrusion