Once you load the game you'll be inside your Garage, scroll through and highlight the tank you wish to purchase the upgrade using
once you've found the tank you'd like to upgrade press
.
On the customization window that pops up you can press
in order to see the module upgrades available for your tank and what level you unlock them at, if an upgrade is highlighted green it means you've unlocked it and are able to purchase that upgrade.
In order to purchase the upgrade press
again to go to the Loadout menu, here you'll see the Modules which you have unlocked by playing matches and gaining tank XP, a red star icon will appear on the top right of the module icons, this red star indicates new unlocked modules, press
on a module with the red star icon and another window will pop up with the available modules, scroll through them with
and press
to purchase the module with Silver and upon purchasing said module the achievement will pop.
This is how you're supposed to unlock the achievement, however for many people including myself it's bugged and isn't unlocking, I know that it's 100% bugged as I've purchased all modules, equipment and consumables for the Tier V Wolverine and it hasn't unlocked, if it unlocks for you I'm happy for you! have fun gaming! :)