For workflow 1 & 2, only https://gerrit.o-ran-sc.org/r/gitweb?p=o-du/phy.git;a=tree need downloaded, for workflow 3 & 4, https://github.com/intel/FlexRAN also need be download
HW and OS requirement please follow document: https://github.com/intel/FlexRAN/blob/master/README.md
You need build FH Lib, FAPI TM and WLS lib firstly, then you could run workflow 3, 4 follow document: https://docs.o-ran-sc.org/projects/o-ran-sc-o-du-phy/en/latest/index.html