g88... your diagram is correct...
adding to Bert's comment, the power cable from bat ---> fuse block ---> distribution block; it is best that you cover the cable. Simple way is to cover the cable all the way with pvc tape or if you lagi rajin (since DIY) you can use flexi which is much more appropiate.
try your best to route the cable at their own lanes. for example (lets say your battery is on the driver side which is right):
Power cable (+ve frm bat), remote wires (fr. HU, amp, other equiptments) are routed on the right side of the car.
RCAs are routed on the center of the car.
Speaker cables are routed on the left side of the car.
this is so that there will not be spider webs underneath yer carpet and lowering the noise production (wee-wee aeroplane).
also approximately every 6", cable tie these cables and tape it down so it won't runaway.
see pic (courtesy of Crutchfield)
happy DIY ;)