So you need to use surveyor units to scan for underground resources (metal, fuel, gold), build mines that extract them, but then also have to transport them (also ammo) to the place where they will be used (buildings, constructors, units) either by using specialized units or via connectors (think Factorio's overground pipes).
It's quite complex, so it's turn based (either simultaneous real time, or sequential turns). M.A.X.2 also experimented with real time (as well as 3D map, inspired by Total Annihilation ?) but sadly it's basically a rushed mess.
Annoyingly this brilliant game has been plagued for decades by memory issues :
Seems to be working as advised (the only thing not working yet would be network multiplayer and some of the various non-critical bugs already present in the original game).
That seems the direction RTS is heading in general, hybridizing with other genres.