I would not recommend starting with Doing Grammar
if you are not very confident with Grammar. I am going through this now and will post a detailed review about this in a few weeks.
I would recommend the following:
1.Either Wren & Martin or any other high school book - if you need more help with your basics
1. You can use the GMAT club grammar book
(starts with more basics than KVF but could have a few things additional and is not as is not as comprehensive KVF
2. Kaplan verbal foundations
3. Doing Grammar
4. Aristotle SC grail & MGMAT SC
I dont believe that Doing Grammar
is absolutely required unless you have plenty of time in hand(if you do, lucky you !!) and would not start with it for sure - who ever said is a good starting point is not at a beginning level.