Update roundtrip.rst
diff --git a/docs/source/roundtrip.rst b/docs/source/roundtrip.rst
index 899d357..24f9ef4 100644
--- a/docs/source/roundtrip.rst
+++ b/docs/source/roundtrip.rst
@@ -74,11 +74,16 @@
 	make openlane
 	# Build the pdk
+	# To build the pdk you need to install magic
 	# make sure to change <directory_name> with the directory you created in step 1
 	# in this case it is caravel_tutorial
 	export PDK_ROOT=~/<directory_name>/pdks # you need to export this whenever you start a new shell
 	make pdk
+	# To simulate you need the pdk with SRAM, to build the pdk with SRAM use
+	make pdk-with-sram
 5. Now you can start hardening your design, for example
 .. code:: bash