Step 1: Obtain your UMLS api key following step 1 here: https://documentation.uts.nlm.nih.gov/rest/authentication.html
Step 2: Run python get_cuis_for_icd.py -k <api key> -f test_input.txt where <api key> is replaced with the key you obtained in Step 1.
Step 3: Replace test_input.txt with your own file with similar formatting.