If your airlock isn't bubbling, don't worry. It doesn't mean that your fermentation isn't working! In fact, many batches of Brewsy never bubble at all.
If you're using a container with a lot of extra headroom, for example, you're not going to see your airlock bubble.
Movement in an airlock is only one indication of successful fermentation — there are a lot of other ways that you can tell it's working, too. If you're unsure, you can find some ways to check whether it's working here.