The fan speed button on the Evolution thermostat sets fan speed for when the system is idle. Fan speed is set by the thermostat (without any user adjustment options) when the system is heating or cooling.
Evolution control wiring is largely 'all or nothing.' Miswiring won't cause malfunctions; it will prevent the system from working at all.
As far as not cooling below 77, how hot was your house before this system was installed? If you had indoor and outdoor temperatures over 100, it will take a while (a day or more) to draw down indoor conditions to something tolerable. If, on the other hand, you've had the system for a few days and/or had livable conditions inside before turning on the AC, then there's probably something wrong.