Question

I'd like to sync a drum machine to my recordings as I am performing all of the tracks and will be adding live drums later in the process. I'm using Studio one Artist, an Audiobox iTwo and a MacBook pro running El Capitan

Answer 1

Depending on the type of drum machine, you will need to set that drum machines MIDI clock to external clock and follow the steps for creating a New Instrument with sync options checked: 

Please read this article for setting up External Midi Devices with Studio One 3:
http://support.presonus.com/hc/en-us/articles/115001352966-Studio-One-3-How-do-I-setup-a-hardware-keyboard-synthesizer-in-Studio-One-3-

1. To use the sounds of your drum machine and sync it to Studio One, you will need to create a New Instrument with the MIDI "Send To" set to your drum machines MIDI port. This allows the sending of MIDI+sync from Studio One to your drum machine.
2. If you decide you want to use the drum pads to record into Studio one. You will need to create a New Keyboard, with the MIDI Receive From assigned to the MIDI in, but don't need the MIDI "Send To." And set this to  Default Instrument Input.

Then, check out this article on setting up to record using an External Device: Setting up to record with an External Midi Device Studio One: http://support.presonus.com/hc/en-us/articles/115001418283-Setting-up-a-Song-to-Record-With-External-MIDI-Devices