To do the things, simply type them with your keyboard.

marshmellow -> gives you a marshmellow on a stick that you can control with your arrow keys.
smore -> turns your marshmellow into a smore
sausage -> gives you a sausage to roast
hotdog -> gives you a sausage to roast
brat -> gives you a sausage to roast
weiner -> gives you a sausage to roast
eat -> eats the food
toss -> toss away your food
trash -> toss away your food

fireworks -> throw fireworks in your fire
firecracker -> throw fireworks in your fire
log -> add more logs to make it bigger (each log burns abou 25 minutes)
crayons -> throw a box of crayons into the fire
paper -> throw some paper into the fire
newspaper -> throw some paper into the fire
photo -> throw a photo into the fire
picture -> throw a photo into the fire
memory -> throw a photo into the fire

avocado -> turns your fire green
green -> turns your fire green
blue -> turns fire blue
yellow -> turns fire yellow
red -> turns fire red
purple -> turns fire purple
violet -> turns fire violet
lavender -> turns fire violet
pink -> turns fire pink
magenta -> turns fire magenta
cyan -> turns fire cyan
brown -> turns fire brown/sepia
sepia -> turns fire brown/sepia
mint -> turns fire mint
limegreen -> turns fire lime green
skyblue -> turns fire sky blue
orange -> turns fire orange
CMYK -> turns fire into CMYK color mode
gb -> gameboy color mode
dusk -> dark "dusk" colors
dawn -> light pastell colors
rainbow -> rainbow colors
aurora -> dark colors with green flame
grayscale -> grayscale color mode
sunset -> sunset color scheme
cottoncandy -> Cotton Candy/Gum Color Scheme
bubblegum -> Cotton Candy/Gum Color Scheme
plasma -> Plasma Color mode
twilight -> twilight color scheme
black -> turns fire black
white -> turns fire white
normal -> turns fire color to normal

blow -> blow air at the fire
poke -> poke the fire

forever -> causes the fire to go on forever without needing to add more logs

water -> extinguish fire and quit the game

fullscreen -> toggle between full-screen and windowed