I've been playing on Classic and one thing I've found is that I need to get a jump start on Satellite Uplinks so that I can keep the panic level under control. However, to build them, I need 10 engineers, and I only start with 6. I can't always afford to take the first abduction mission that offers +4 engineers, because often there are high-panic countries that I need to head to instead.
I've noticed that eventually the workshop unlocks and I can build it to get the engineers I need, but I don't know exactly what triggers it. I'd like to know, because if it's something I can control, it means I can get Satellite Uplinks going more quickly.