Update README.md

Author: her3ticAVI

README.md

@@ -29,6 +29,8 @@
 > Failure to properly provision Virtual Machine will cause failure during install.
 > You MUST use the VM provided for this class to work, some of the labs in the VM have dependencies pre-installed meaning if you don't use the docker to walkthrough this course you will have issues with dependencies and setup.
 > These labs will NOT work with ARM architecture
+>
+> Downloading and extracting the OVF file required for this class will take a large amount of time. Please allow yourself ample time to do so before the class begins.
 
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