Make sure your bottle and stopper/cap and whatnot is sterilised and totally clean.
Rosemary... Make sure you wash it, and leave it a little while to ensure any creepy crawlies have vacated before you bottle it! 🐜
Glass bottle with inserted rosemary.
Pour oil into the bottle using the funnel if you need it.
Stick the cork in, or screw the lid on etc. Leave in a dark place (like the under-sink cupboard) for a couple of weeks to infuse.