For this you need 65000 credits to unlock the second and the 3rd cargo and 4850 reputation to unlock the small intestine.
After that buy 10 small intestines ( 6 meters each ).
For a quick and full achievements guide video check the link below:
Timestamps:
00:00 Intro
00:36 Flesh Replacement, Facial Repercussions Achievements
01:12 Learn to Trade + Hello, Scum Achievement
03:19 Committed, Binding Terms, Reputable Trader, Doubled Investment Achievements
03:56 Organ Toucher, Organ Fondler Achievements
04:36 Oxygen Measurements Achievement
04:54 Meatshare Achievement
05:21 Long Odds Achievement
07:08 Stiffed Competition, Organ Monopoly, Severed Contract Achievements