Add readme instructions

Author: dhairs

README.md

@@ -1 +1,35 @@
 # LHRe 2025-2026 Monorepo
+
+[![Postsubmit](https://github.com/LonghornRacingElectric/lhre-2026/actions/workflows/postsubmit.yml/badge.svg)](https://github.com/LonghornRacingElectric/lhre-2026/actions/workflows/postsubmit.yml)
+
+This repository is a monorepo for the LHRe 2025-2026 codebase. It contains all of the code for the season,
+including firmware, telemetry server code, documentation, tests, and build configurations.
+
+The preferred build tool is Bazel. However, other build tools are supported depending on the project.
+Firmware projects still support using `make` for compatibility and each `Makefile` is located in the root
+of each firmware project directory.
+
+Because Bazel automatically manages dependencies and toolchains, it is our preferred tool for
+allowing quick code updates without needing to worry about other machines having the same build environment.
+
+By default, Bazel will attempt to build all targets for the `arm_none_eabi` architecture.
+This can be changed by specifying a different target platform or config in the build command. For example,
+`--config=firmware` will force the `arm_none_eabi` toolchain to be used. Check the `.bazelrc` file to
+see the other available configurations.
+
+To build all targets: `bazel build //...` (will only build firmware by default)
+
+To test all targets: `bazel test //...` (will only test firmware by default)
+
+## Contributing
+
+Note: Code cannot be pushed directly to the main branch.
+
+We now require that the code being written be tested and approved by a reviewer before it can be merged.
+This will allow us to make sure builds are not breaking due to untested code, and will enforce style
+and code-quality checks. Create a new branch for each feature you work on, and then open a pull request
+(PR) for your changes. Reviewers will not be assigned automatically, so make sure to request a review from
+someone on the team.
+
+Each PR will go through a review and presubmit, if the presubmit fails, you will not be able to merge the code.
+If you need to make changes to your code after opening a PR, you can push new commits to the same branch and the PR will be updated automatically.