Start off by taking your pre-program progress pictures.
Do not skip this! Seriously, your future self will thank you.
Here are the suggested poses.
There are a couple of measurements that should -ideally- be performed right at the start. Some of them are required in the US Navy body fat % calculations, so why not just do all of them?
For weight measurement a basic scale suffices, preferably one that you can keep using to avoid inter-scale variability.
Always weigh at the same moment each day, ideally right after waking up (and urinating).
Optional: Medical Tests
It is not required, but advisable to take some pre-program blood and urine samples and test the following markers.