Add build instructions to README.md

README.md

@@ -31,3 +31,15 @@ If you have custom hardware and you want to add support for it in the official r
 1) Go to https://github.com/vedderb/bldc and use the github fork function.  
 2) Make your changes, test them and make a pull request to the main repository.  
 3) If the pull request gets accepted your hardware will become part of the next official release. It will show up in the binary beta typically after a few days and in the stable version the next time a stable release is made.
+
+## How to build
+
+Download and install Qt 5.15 open source, make sure to check the 5.15.x option in the installer.
+
+Before you can build from the command line you need to build it at least once from the UI. Open qtcreator, open the project vesc_tool.pro, and configure it (all defaults), then build/run.
+
+Now add qmake to your path and you should be able to run the build_lin scripts.
+
+It will complain about res_fw.qrc missing. To get around that, you can un-comment the "exclude_fw" line in vesc_tool.pro - but then you will not have the built-in firmware files included in your tool.
+
+Hopefully someone can add how to also include the firmware files...