Installing an Upgrade is similar to installing a module, with a few notable differences.
The important part is that you need to point the Upgrade installer to the correct place where the full game currently resides. Since the Upgrade is not a standalone game, and everyone's installs differ somewhat, the automatic detection of your current installation path is not fail-safe. Please double-check the install path before installing.
Upgrades often require a specific version of the base game to be installed. In the case of CMBN Upgrade 2.0, this is version 1.11. In the case of the CMBN 3.0 Upgrade, it is version 2.12. So please make sure you install the latest patch first before upgrading.
Upgrades update both the base game and any modules you have installed automatically. It is not necessary to download and install individual upgrades for each module.
Unlike Patches, Upgrades will require you to activate the game again with your Upgrade license key. That key is saved in your online account at www.battlefront.com/store for downloadable items, and printed on the product itself (usually the case or manual) for mail only items. Note: This key is the only key you'll need in the future, you won't need any of the previous license keys you have purchased. It gives you a fresh 4 (2+2) activations for the game and all modules.
Do not install non-Upgrade patches after upgrading. If you upgrade to v2.0 and then install the v1.11 patch, you will DOWNGRADE your game to v1.11. This should be obvious, but it's worth stating explicitly.