The zero in your Carbide Create (CC) is an arbitrary location. For instance, say you told CC to use "top of stock" (in the Stock Thickness area) and a Toolpath Zero of lower left.
When you're done with your design, one generates "G code" - instructions that command the machine to create your design. These instruction are performed relative the point you defined.
Now one places the stock that matches that was defined in CC in your machine. Where one places their stock on their machine isn't really important... where it is the most logical: it can be fixtured so that it cannot move when machined and it is easy for the operator to access it.
Yes, this means that the X0Y0 of your CC part is, most of the time, not aligned with the zero of your machine. In fact, virtually all of the time we're not interested in the machine zero at all.
How one proceeds from here is somewhat up to how one conceptualizes their CNC machine. I will explain things the way I teach it. Normally, I do all of this over a machine but let's try this entirely by description.
Say the stock defined in CC was 4" wide, 5" tall, and "0.5" thick. We need a piece of stock a least that big so we obtain our goal. We now have to think about fixturing (e.g. clamps). How does one keep the stock from moving when it is machined?
One common technique is to cut a piece of stock larger than necessary - 5 x 6 (still 0.5" thick) - so one can position the clamps around the sides and have a unobstructed 4x5 area within the fixtures. We can set up the necessary "zeros" anywhere within the boundary that is entirely free of the fixture (no collision will be possible because we're never there).
Now one needs to align the zero point from CC with the stock in one's machine. We do this by jogging (moving) the gantry around with the necessary tool in it. One said "top of stock" so one needs to have the tool touch the top of stock and declare this as Z0. Likewise, the corner ("bottom left") has to be assigned - X0Y0.
Let's see. Get out a ruler. Find the left corner closest to you. Measure in 1" from the left edge and 1" away from the edge closest to you. Mark that spot. Move the gantry such that the tool is over that spot and just barely touching the stock . Set X0, Y0, and Z0 there.
Review: Now one has Z0 at top of stock and X0Y0 at an acceptable location. The virtual world of CC is now aligned with the physical world of CM. We're ready to cut.
Where to chose one's X0Y0Z0 and how to assign it within your machine comes with learning and practice. One creates a "work flow", a documented procedure one uses to solve things.
The method I presented above is one of several techniques. Over time, and depending on what one uses their machine for, one will develop multiple "set up the zeros" work flows. This is where things like edge finders and laser pointers come in. That's for another time...
Once one understands things conceptually, all that is necessary is to learn how to achieve it when using Carbide Motion (CM).
There are "jog" (move) and "zero" (set the zero of a job) tabs in CM. With CC, if one uses the larger than necessary method, one can ignore the offset column in the zero tab (that is for a more advanced learning session).
When one's tool touches the top of stock, go to the zero tab and hit "Zero Z". When you've found the location for X0Y0, go to the zero tab and "Zero X" and "Zero Y".
Do things make sense now?