methods section of dissertation

Hey! Although I didn't study biomedical science (BSc Applied Biology, MSc Aquatic Pathobiology), I can offer some advice.
While researching it’s important to keep a note of the experiments you've done (basically the methodologies you have applied), and walk through them chronologically. Subheadings are great as they help make the section more ‘digestible’. Break your entire thesis down experiment-wise, then talk the reader through what you did. It’s important you don’t discuss why you picked a certain methodology here: that should be included in your introduction / Lit Review or mentioned in the discussion. I can't suggest an overall structure, as this is a discipline I'm not familiar with, but short and succinct sentences are generally preferred across the sciences.
A ‘good’ methods section contains enough detail that I (or someone else who might not be very familiar with the discipline I.e. biomedical science) can replicate the experiment the same way you did. To write mine, I broke all of my experiments down into their respective steps, then re-wrote them into complete sentences.
I come from a more research-orientated background, but hopefully some of this helps. If in doubt, reach out to your supervisor. It’s why they’re there 😄 Good luck!