Whenever you create a Geniuslink account, you are given a unique identifier for each group that you create. When you open your account, you will have a single group (called Default), and it will have a four to six digit code that is associated with it. 

Each group will have a unique Traffic Source ID which can be used to separate your links. If you're building links programmatically, or using the JavaScript snippet, you can select which group those links fall under.

1. Log into your Geniuslink Account
2. Go to the Groups page
3. Look at the number next to your Group name(s).
4. That number is the TSID for that specific group.