I couldn't find the building/command to upgrade armor/attack of my units. Google is no help either. The other guys can do it, and when I ask them how to do it on ally chat, they just ignore me/kick me from the lobby.

1 Answer

Upgrades are purchased at the 'Upgrades and Heroes' building, with the appearance of the campaign 'Merc Compound'. The building hotkey is E, next to the Blink ability, as shown in the image below. Relevant Source

When selecting the building there are four buttons for heroes. The final three buttons are to access the upgrades. The hotkeys for Terran, Zerg and Protoss technologies are Z,X, and C, respectively. Selecting these buttons opens menu for that race's upgrades.

For example, after pressing Z, you will see the Terran upgrades visible below.