Yes, it can be confusing sometimes when you read conflicting things!
Yes, you should wait to start exercising until P1 unless you've been doing it for a long time and feel well enough. Those who haven't been exercising should definitely wait. When you start, start small and build up so you don't hurt yourself or get discouraged, okay? You'll find tons of info, help, and great advice in the Exercise and Ladies Who Lift forums here on 3FC. They have taught me so much! Just make sure that you eventually include both strength training (weight lifting/bearing exercises) and cardio (exercises that get your heart moving fast) several times a week, if possible. The strength training will help build muscle, which actually burns calories, even while you're sleeping, and takes up less room than fat, so it makes you smaller! The cardio will not only be good for your heart and lungs, but can help you burn fat.
How far along are you on P1? If you are a day or two from the end, you can probably just monitor for cravings and keep going if you don't feel any. However, if you have about a week to go, I'd start over for the most effectiveness. Honestly.
That's just my humble opinion...but you get the most from SBD when you do a good, clean P1 with no cheats, even the unintentional ones (I've done it too...the hardest thing for me is carrots...it's hard not to think of them as a diet food that's okay!
Best of luck and glad to have you here with us!