document generate crates list

docs/writing-easyconfig-files.md

@@ -672,6 +672,19 @@ Here, the template strings `%(name)s` and `%(version)s` will be
 substituted from the `exts_list` entry elements ("pyCAP" and "0.1",
 respectively), not from the easyconfig values.
 
+### Generate a crates list {: #generate_crates_list }
+
+To generate a crates list for a package:
+
+1. Download and unpack the source code for the package you wish to build
+1. Change into the directory containing the top level `Cargo.toml.
+1. Run `python -m easybuild.easyblocks.generic.cargo .`
+
+If there is not already a lockfile then you may need to do the following to generate it:
+
+1. Load a recent Rust module
+1. cargo generate-lockfile
+
 ### Configure/build/install command options {: #configure_build_install_command_options }
 
 - **configopts**: options for configure command