Step 1: Heft thousand pound air conditioner up stairs to the furnace that is your office space.
Step 2: Turn on space heater which doubles as a fan and turn dial to Fan-Only so you roast just a little less while you work.
Step 3: Lay out all pieces and read instructions as to which piece is which, speaking each item out loud for maximum learnability.
Step 4: Sweat.
Step 5: Try to figure out how to fit three plastic things together to create "window panel assembly" to fit in window but window is tiny and there's no way all three panels together will fit in window. Two panels together (main panel plus one extension panel) will fit in window but instruction book doesn't say you can use two panels, only three, and you don't want to disobey instruction book. Try putting two panels in window. They fit, but the window opening is vertical, and when you let go of the two panels, the extension piece slides back down inside the first panel. (You have missed the part in the instruction book about using blunt-tip screws to secure panels together.)
Step 6: Read part in instructions instructing you to use enclosed strips of foam to cover edges of extension panels. Instruction book doesn't state whether "edges" means long edges or short edges.
Step 7: Repeat step 4.
Step 8: Watch many YouTube videos. These videos will omit the part of the instructions you didn't understand where you can use the blunt-tip screws to secure panels together (which, in your defense, you missed because the vague language made it sound like the screws were to secure the panels to the window).
Step 9: Realize you've got the space heater set on Heat rather than Fan-Only and say the eff word and repeat sweat 4, I mean step 4.
Step 10: Finally understand the thing about the blunt-tip screws. Remove two blunt-tip screws from screws packet.
Step 11: Realize you forgot to stick the foam pieces to the edges of the plastic panels that will end up in a landfill someday with the rest of all this god-forsaken plastic stuff. Stick foam pieces on panels.
Step 12: The blunt-tip screws are now lost.
Step 13: See step 4. Also consider crying a little.
Step 14: Sit down and start to write a blog post about it because fuck it. And, hey, this is more fun. Feel proud of yourself and begin to gain a warm feeling of self-recognition.
Step 15: The window panel assembly is now lost.
(You should really be a better housekeeper.)
Step 16: Locate window panel assembly and, miraculously, blunt-tip screws and take it all, with screwdriver (wow, you're a genius, you remembered to bring the screwdriver), to window. Sit in blast of hell from window and lay two-part assembly upright in window, being careful to keep panels fully extended, reach for first screw and – how the goddamn hell are you supposed to keep the panels extended and screw in the screw at the same time with only two hands? Every time you go to screw in the screw, the extension panel falls down. The screwdriver is one of those magnetized ones, and you try just using one hand for the screwing but then the fucking screw falls out. OK, fine, stick your fucking foot out through the fucking hole in the plastic window panel and use your fucking big toe to hold the works together while you use both hands to screw in the fucking screw.
As you go to secure the second screw, a crow dives in a black flash right past your window, passing so close you can see the feathers, swooping in a great arc toward the grass and then flying off into the sunny neighborhood.