First thing you want to do, is start a brand new, un-modded character, for the smoothest and easiest experience possible i suggest picking Argonian as it allows you to skip an entire step, second of all, i take no responsibility for any broken keyboards, monitors, or sanity as an effect of attempting this achievement.

Step 1 - Don't Die
This may seem like a given, but what alot of people don't know, that in order to not be executed in Helgen, you must open the console and type in this sentence exactly, "Mr. Executioner, i love your fursona, oh Mr. Executioner, please spare me", once this is done you will be allowed to walk free.

Step 2 - Don't Die Again
This also may seem like a given, but Alduin hates furries and attacks Helgen, fun fact he speaks in dragon tongue and says "I hate furries, scalies for life, N*****s!" because Alduin is also secretly racist.
If you picked Argonian, you can skip this step.

Step 3 - Go with Ralof
Ralof was nice to you, he gave you an extra flinstone gummy in class that one time, Hadvar never did anything for you, he just spread rumours about you enjoying eating dog poop, so pick Ralof or your not invited to my birthday party :(

Step 4 - Dont anger Ralof
He has a knife, and your hands are bound.

Step 5 - Exchange sexual favours for your freedom

Step 6 - Be Free!

Congratulations, you are now the Elder Scrolls V: Skyrim that this city deserves!