This works the same in Campaigns V2 and Legacy Campaigns (V1) — in V2 the button is labeled Tracked Link instead of the chain-link icon, but it does the same thing.
Here is how to create a trackable link in a Rally platform campaign.
Create a campaign or edit one already created
Add a link using the Add a Link (or Tracked Link) button
Include {{rally_link}} where you want the link inserted
Can I include more than one link?
Yes. Each campaign supports one tracked link, added with the chain link button. If you want a second link, type or paste it directly into the message body. It will work normally, but it won't be shortened or tracked. (Not recommended: we suggest one link per message to keep your call to action simple.) Avoid public link shorteners like bit.ly for the extra link, since carriers may flag them as spam.
Legacy Campaigns (V1) only: Seeing "Campaign publishing is restricted due to missing rally links for some recipients"? The system creates a unique tracked link for every contact in your campaign, and that takes a moment. It usually takes a few seconds, but larger contact lists can take a minute or longer. Wait briefly, then refresh your browser and the warning should clear. You don't need to change your message. If it is still there after a few minutes, contact our support team.