Hi Sameer,
I have a detailed explanation of the OSPF neighbor adjacency here:
In the LOADING state, LSUs are exchanged and when that’s done, the routers will show that they are synchronized. Once that’s done, they have everything they need to run SPF.
You can see the adjacency and SPF in action (and in the right order) if you enable these two debugs:
debug ip ospf adj
debug ip ospf spf statistic
Try that next time you have two routers, it’s interesting to see.
Hope this helps!
Rene