Any question answered...

So I am putting together a road bike for first time;
The brakes are fine, adjusted and working.
With the gears I've done following;

1. Installed both derailleurs
   
2. Installed the chain
   
3. Did top adjustment for FD and RD with chain on small chainring and smallest sprocket
   
4. Got a cable running through RD ..
   
   

Now the issue is to make the low adjustment on RD I have to shift to largest sprocket but after 8 shifts I am running out of cable (cant shift any more) so what have I done wrong? Cable too short? Due to some routing error previously I may have shorter cable than needed. I can always buy new cable/inner.

RD looks like this in the current position: