diff --git a/clang-tools-extra/clangd/README.md b/clang-tools-extra/clangd/README.md
--- a/clang-tools-extra/clangd/README.md
+++ b/clang-tools-extra/clangd/README.md
@@ -17,3 +17,18 @@
   channel](https://discord.gg/xS7Z362).
 - user questions and feature requests can be asked in the clangd topic on [LLVM
   Discussion Forums](https://llvm.discourse.group/c/llvm-project/clangd/34)
+
+### Building and testing clangd
+
+For a minimal setup on building clangd:
+- Clone the LLVM repo to `$LLVM_ROOT`.
+- Create a build directory, for example at `$LLVM_ROOT/build`.
+- Inside the build directory run: `cmake $LLVM_ROOT/llvm/
+  -DCMAKE_BUILD_TYPE=RELEASE -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra"`.
+
+  We suggest building in RELEASE mode as building DEBUG binaries requires
+  considerably more resources. You can check [Building LLVM with CMake
+  documentation](https://llvm.org/docs/CMake.html) for more details about cmake
+  flags.
+- Afterwards you can build clangd with `cmake --build $LLVM_ROOT/build --target
+  clangd`, similarly run tests by changing target to `check-clangd`.