How to connect Variables to I/O?

Hello,

I'm completely new to ctrX programming, but did Siemens, Beckhoff and Mitsubishi in the past. So I know a bit of PLC programming. That said, I still have trouble with something I would say is basic...

Please correct me, if I do things wrong, but I thought I had to code my PLC program in the ctrX PLC Engineering and my hardware in ctrX I/O Engineering!? Because I have not the slightest idea how to "connect" those two? 

I have my in/out variables in a variable-table on PLC side as:

var_1 AT %Q* : BOOL;

and so on. So... how I can I tell my I/O config that they are there?

In the manual for the PLC engineering and the part about I/O config I found a screenshot of the "device" tab with a PLC and a DPMaster and a few devices on there. Aside that I have EtherCat, do I not need I/O Engineering? Do I all in PLC Engineering? And if so: How? Because I can't find a way to include any communication-master there. I can do that in the I/O Engineering without a problem. 

So: Can someone tell me, what I do wrong or where to look where that is explained how to do? I'm a little bit lost...

Thanks in advance!