diff --git a/tools/quartus/run_altera_simlib_comp b/tools/quartus/run_altera_simlib_comp
index 283e2190c3435d3614e76a2c19ddc846800b07db..1f165c48acde51590c90f741922c4d7a940aac40 100755
--- a/tools/quartus/run_altera_simlib_comp
+++ b/tools/quartus/run_altera_simlib_comp
@@ -33,10 +33,15 @@
 # Usage:
 #   Assume $MODEL_TECH_ALTERA_LIB=/home/software/modelsim_altera_libs/14.0a10
 #
-#   First run the script in some user directory that where $RADIOHDL is known. Use the output directory that will fit $MODEL_TECH_ALTERA_LIB
-#   > run_altera_simlib_comp 14.0a10
+#   First run the script in some user directory that where $RADIOHDL is known. Use the output directory that will fit the
+#   $MODEL_TECH_ALTERA_LIB that is defined in quartus_version.sh in set_quartus.
+#   The FPGA device family library needs to be compiled separately. To compile the vhdl and verilog for the arria10 library for the
+#   unb2 tool settings defined in set_quartus and set_modelsim do:
+#
+#   > run_altera_simlib_comp unb2 14.0a10 arria10
 #
 #   Then use 'sudo' to move the directory to the protected central project directory that is set by $MODEL_TECH_ALTERA_LIB.
+#
 #   > sudo mv 14.0a10 /home/software/modelsim_altera_libs
 #