On the Crimson Communications settings click on Network, and enable the port first. Then set the IP address details for the G3. You have probably already done this.
Then click on Protocol 1 and then hit Pick...
Choose Allen Bradley under Manufacturer, then you can choose DF1 Master, or DF1 Master via EIP. I have had better luck when I pick just plain DF1 master for getting the Emulator to work through my particular PC to a real PLC. I am not sure why this is. Either driver should work though. The Native Tag drivers are for Controllogix and CompactLogix applications.
This will populate a "PLC1" device under Protocol 1. You can rename the device now or at any time if you want. Next, click on that device, under Device Settings > Device, you probably will want to pick Micrologix. Then set up the IP configuration for the Micrologix1400. All of the other options can be left at the default values. If you plan to read real input points,
you may want to disable Spanning Reads. I have had issues with that setting dealing with a SLC and smart cards. One other quirk about tag imports:
See posts #4 and #5 here.
Next, at the bottom of that window, there is a link called Create Data Tags. This is where you will import the tag database from RSLogix500. I have not used this new and improved version, but it appears you now have the option to create Crimson tag names based on symbol names and you can choose how many lines from the RSLogix500 descriptions get imported into both the Crimson Tag Names and labels. It looks like the default settings should be pretty good, but if you don't have symbols, you may want to check the box for Data File and Offset.
I am pretty sure this is designed to work with a database csv export from RSLogix500.
Hope this helps
Paul