Hi all!
For anyone using 9.6 you can also use the following new partition actions:
Create Default Partitions - This will wipe disk 0 and then create an appropriate partition scheme for your device. By appropriate I mean that on UEFI it will convert the disk to GPT and add a UEFI boot partition, MSR partition and OS partition. The Boot Partition will be mounted as S: and the Windows partition as C:. On BIOS devices it will make the small bootable partition and then the OS partition, once again mounted as S: and C: respectively. This makes it so when you later try to apply the image or inject the unattend you can do it to the C: drive and when you run BCDBOOT you can point it to the S: partition with full confidence. This is primarily for use with ImageX or other file based imaging tools before applying the image.
Auto assign partitions - This one is similar to create default partitions, but instead it will scan the mounted drives and try to find the boot partition and the OS partition and assign them to S: and C: respectively, giving you the same end result as the Create Default Partitions action. This is primarily for use with ImageW or other sector based imaging tools after laying down the image since the partitions can be assigned indeterminate drive letters.
Finally, if using 9.6 I HIGHLY recommend starting with the deployment template wizard. It will create a template that will format the drive, deploy an image, run BCDBOOT (if needed) and allow you to choose whether you want HII, to inject an unattend, etc. It will also install the agent, run policy sync and install any mapped software (a new feature as of 9.5 SP2). It takes about 1 minute to create the template and it gives a high success rate. It basically follows what slimowski just talked about above, but it's all automatic to make it easier for you.
Edit:
If you're still on 9.5 SP2 then the wizard and those actions don't exist yet. These are new in 9.6.