I assume that you're setting your timing?
The timing mark on your flywheel should be lined up with the marker as in your photo.
Timing is usually set with the number 1 piston at the top of it's cycle, BUT at this time both number 1 and number 4 pistons will be at the top of their cycle, so be careful here because your timing has to be set only for number 1 piston.
Number 1 cylinder should be in the firing position and to test this have a look at the exhaust valve on number 4 cylinder (number 7 valve). This should just be about to open.
A bit confusing but search on this forum for "engine animation" which I put up about a year ago.
http://www.renault4.co.uk/forum/threads/4-stroke-animation.7824/
With that done, put some grease on the little gear and stick it to the bottom of the distributor.
Line up the dizzy cap so number 1 lead faces approximately to the front right hand side wheel.
Then just put the dizzy with the gear attached into the hole.
There is no correct position for this little gear, it can fit into any position.
A long story but I hope it helps. Just ask if you need more info