Compilationon Archer2

[annajcrawford]

Computing system (please complete the following information):
Archer2

Issue Type
Compilation on new system

Error message or symptoms
When I run: bash compile_cray.sh, the output reads:
-- checking for thread-local storage - found
-- Could NOT find MPI_C (missing: MPI_C_LIB_NAMES MPI_C_HEADER_DIR) (found version "3.1")
-- Could NOT find MPI_Fortran (missing: MPI_Fortran_LIB_NAMES MPI_Fortran_F77_HEADER_DIR MPI_Fortran_MODULE_DIR) (found version "3.1")
CMake Error at /lus/cls01095/work/y07/shared/utils/cmake/cmake-3.18.4-Linux-x86_64/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:165 (message):
Could NOT find MPI (missing: MPI_C_FOUND MPI_Fortran_FOUND) (found version
"3.1")

  Reason given by package: MPI component 'CXX' was requested, but language CXX is not enabled.  

Call Stack (most recent call first):
/lus/cls01095/work/y07/shared/utils/cmake/cmake-3.18.4-Linux-x86_64/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:458 (_FPHSA_FAILURE_MESSAGE)
/lus/cls01095/work/y07/shared/utils/cmake/cmake-3.18.4-Linux-x86_64/share/cmake-3.18/Modules/FindMPI.cmake:1721 (find_package_handle_standard_args)
src/CMakeLists.txt:5 (find_package)

-- Configuring incomplete, errors occurred!
See also "/home/n01/n01/annac/HiDEM/HiDEM/build/CMakeFiles/CMakeOutput.log".
make: *** No targets specified and no makefile found. Stop.
make: *** No rule to make target 'install'. Stop.

Describe the context
I'm working with compile_cray.sh and HiDEM-cray.cmake.
As I understand it, PrgEnv-cray is loaded automatically on Archer2. I have commented out #module swap PrgEnv-gnu PrgEnv-cray in compile_cray.sh for this reason.
I also ran module load cmake.

Expected behavior
Successful compilation

Error Log
CMakeOutput.log

Any suspicions/clues as to what the cause might be?
Perhaps I am not loading the MPI component 'CXX' correctly? The Archer2 Quickstart for Developers page mentions using a command like: export CC=cc export CXX=CC export FC=ftn export F77=ftn export F90=ftn. I tried this but obviously don't have it set up correctly.