I run 3 dupes until I'm done with all my research.
Never ever use algae deoxidizers.
First build 2 outhouses and 3 beds spread apart, because they breath out co2 and can disrupt other people's sleep if oxygen levels are low. But you shouldn't let your O2 levels get low because you'll need 6 terrariums to keep 3 people alive (notice the free light source). Same goes for food, you'll need 6 (7 to be safe) mealwood plants to feed them.
Do not let them go underwater, or even near water until you have a working shower (the outbound pipes need to go up 2 tiles to work properly).
Always always always research in this order first: Food then Decor
I used to go for the electolyzer and hydrogen genny, but you don't really need it if you can your biodistillers up and running.
electrolyzer is just in case you run out of algae, but you need to get the hydrogen genny right after so you can deal with the hydrogen.
you only need 1 artist (usually get someone with 5 creativity and don't let anyone else do the art)
1 person on research
1 person to cook
If you want easy mode, get one of each from the start screen and make sure they all have diver's lungs
Notice the terrariums at the bottom of my main (only) shaft because they can suck up CO2. There's still a ton of algae I haven't even dug up yet and I have almost all my research done. Beds always go up a level because O2 rises, but that's not important BECAUSE YOU HAVE 6 TERRARIUMS, RIGHT? But really, low concentration O2 and making them dig in water before they can shower makes their stress unmanageable.