If your Venue console has an internet connection, all you have to do is click "I'm online" the first time you use the plugin, and then enter your login info and click through the activation prompts.
Here's how to do it if your console doesn't have internet:
First, trial licenses aren't created automatically in the offline authorization process, so just go to Create Offline License, select whatever plugin you're interested in, and click "Create license." Now you can go on to the offline authorization process below.
If the plugin activation window isn't already open, click on the key icon on the lower right corner of the plugin window. Next click the "I'm offline" button, and then click "Save to file" to save your machine ID. Save the file to a flash drive, or any kind of removable drive. Then, on your online computer, open a web browser, go to Manage Devices, click "choose file," and upload that machine ID file that you just got. Click "activate." Then click "Download license file" and you'll get a file that you can upload on your offline computer, by clicking on the "open license" button in the plugin window. Then finally click "activate" and you're activated.