Hi,
You can see the guidance regarding the requirement to register for VAT as in terms of taxable turnover here:
Working out whether you need to register
If you are providing holiday accommodation through Airbnb, then this would normally be a taxable supply and you would need to consider this as taxable turnover when deciding if you need to register for VAT.
As a sole trader, everything you provide in terms of goods and services would go towards your turnover, as you as the sole trader, is the legal entity for VAT purposes. You can see guidance here:
Hotels and holiday accommodation (VAT Notice 709/3)
Thank you.