Although not an HVAC man, I have done it using a basement-mtd upflow gas furnace. You need precharged refrigerant & return lines, thermostat & 4-wire control line, @least 10ga powr wire (chek local code), dedicated ckt, a prepared spot for the outside unit inc a concrete/styrofoam pad, local disconnect  plug within 3 ft of the outside unit. Pvc condensate drain line & pump if straight gravity drain is not possible. In humid weather, the system generates upward of 1 gal/hr. No small matter! Install A-coil in plenum chamber of furnace. First, install rails if necessary. Rig drain line. Spot outside unit. DO NOT remove mfg plastic plugs until you are ready to connect lines! Rig power lines & thermostat/control lines. You may have to bore through wall(s) for the pwr & fefrige lines.I modified  a basement window. When all of this is done, connect refrige/return lines, chek for stray hand tools, etc & turn on the system. Should go right off. Be on deck to watch for malfunctions. If any of this seems daunting, hire a pro!! However, knock your own holes in walls. Pros tend to assault with sledge hammers requiring repair by another pro like a brickmason. Good luck! Mine took the house down from 95 to 64 in 4 hr.