IS DR automatically elected in OSPF or is it a manual process?

DR is elected automatically  as a process .

A DR is elected :

1. Priority  : it can be from 0 - 255 but by default priority of all interfaces is 1 so it's a tie. 

- Lowest Priority is Preffered.

2. Router - ID : As in ospf every router elect it's router-id itself . so Higher Router-Id is preffered.