To use this conversion guide you will need a copy of S3: Expedition to the Barrier Peaks.
This conversion guide allows DMs to run the original module with 5th Edition rules. There is a reference sheet for random and planned encounters.
In 1976, Expedition to Barrier Peaks was introduced at the Origins 2 gaming convention. Then, in 1980, TSR published the module Expedition to Barrier Peaks with the module code S3 written by Gary Gygax. In the course of the module, new creatures that had never appeared before were introduced. And then subsequently killed many adventurers.