Take all the Carriers out. (you will need to do this some time in the future to clean the chuck anyway so now's a good time to learn)
Now look at the scroll down one of the carrier slots.
Turn the scroll until you can just see the start of the spiral (outer edge) appearing in the slot.
Take carrier No.1 and slot it in ensuring when you turn the scroll it starts to pull the carrier in.
Make sure you only advance the scroll until you can just see it in next slot.
Now load carrier No.2 and engage it in the scroll and advance scroll to slot 3.
Proceed until all 4 carriers are engaged.
If done correctly all outer edges of the carriers should be protruding the same distance.
It is very easy to pick up the wrong tooth on a carrier and dependant on the chuck one carrier may have one less or only partial tooth. (not likely with Axminster Carriers)
Make sure carriers 2-3-4 are pushed all the way in to engage the scroll, bearing in mind the possibility of the missing tooth, (most unlikely with an Axminster Carrier) that's where the noting of the outer edge of the carriers are positioned in relation to the chuck body when loading is useful.
With any chuck if you put your carriers face down alongside each other in their order 1-2-3-4 the you will see the sloping pattern of the scroll teeth and if one of jaw carriers has a partial or missing tooth it will be obvious and noted as to the one needing more care when engaging in scroll. (It may be No1 or No.4)
On one chuck I fixed for someone it was Carrier No. 1 and that was what was causing the error when loading as it needed to be loaded last not first.[I.E. after the scroll had made a 360 turn with 2-3-4 loaded)