Hexagon base is small, efficient, and brutal. There’s only room for four (or eight if couples) colonists at any given time with no plans to expand that.
Mods
This is base game, not Royalty. Combat Extended (not CE Guns, but I get the ammo types and turrets), Dub’s Paint Shop (to paint the power armor), otherwise vanilla.
Colonists
Most of them have a similar loadout to this (every day carry for my team, one has a sniper, three have assault rifles. I use the molotovs a lot in close range, fire is so strong in CE. This image was taken the summer before the main screenshot submission
No Killbox
Most of the time, I step outside the colony walls to take down threats before they get to the main base. If there are mad animals, I can close the north door (which usually remains open) to stay safe. With large raids, they funnel in to the north where my multiple incendiary IED trap sets a lot on fire, before starting to take damage from the heavy auto turret and my colonists.
With sappers, they usually break in on a single wall (not the edge rooms) where I can hit them with mortars (before they get in) and my mobile KPV turret and colonists after they break. I tested a 50-person tribal raid for fun – they broke in above the south solar panels, destroyed walls to south greenhouse and research area, killed one of my four colonists before I was able to repel them.
Normal raid is 3-10 for my wealth/difficulty.
Greenhouse
Temps get to -30F in winter. I have the heaters hooked to the main power grid, and the sun lamps are on a separate loop, only attached to the four solar panels, batteries, and backup generators. This helps with power spikes in the morning not shutting down my whole base before the solar panels come on (and in winter there’s not much sun).
I have a switch that lets me connect solar panels to the main grid if needed. Each greenhouse has two partially built campfires, so if I get a solar flare in the winter, I can quickly finish building the campfires and that will keep my plants alive and warm until the heaters come back on, this means I am almost never at a loss for food. If I lose my plant food source, there’s always hunting to fall back on, and the Nutrient Paste Dispenser makes a little food go a long way.
If you don't understand how the parts work, what they do, how delicate the connectors are... Without any experience you can't know what not to do. Trying to build a PC, a lot can go wrong if you don't know what you're doing. That a lot of expensive parts that can be destroyed in a blink of an eye if you make a mistake.
You say all the parts fit only one way. Well, that depends on how clumsy or ignorant the builder is. Or both