upd doc

README.md

@@ -54,7 +54,11 @@ Obtain the pre-built protobuf compiler and library (version X) from here: (URL)
 **Option 2:**
 Copy files from docker image. If you built the main docker image then protobuf has already been built and you can copy the files from there:
 
-!INSTRUCTIONS!
+```bash
+mkdir -p opt/usr
+docker-compose cp builder:/usr/i686-w64-mingw32 opt/usr
+docker-compose cp -L builder:/usr/bin/protoc opt/bin
+```
 
 **Option 3:**
 Build protobuf inside a container. Use either the "builder" or "clang-cl" docker image to build protoc and libprotobuf and adjust your CMAKE_FIND_ROOT_PATH accordingly: