AI training remote work - tax

Hi I am looking for work currently, and am noticing that there are a lot of opportunities for me in helping to train AI models for $30 - $50 dollars an hour (e.g. Outlier/Data Annotation). However, they are payed directly to PayPal in USD, and therefore I'd need to ensure I am paying the correct tax on this income if I were to earn enough. I understand that I can earn approximately £1000 in any given year on this income before paying tax, but then my understanding ends. If I were to start some of these jobs, and the pay comes in, what is the process? As far as I can tell I fill out a Self Assessment form, but I wanted to be clear on this before I go on and potentially start earning. For example would this work be considered self-employed, or would it be foreign income? Any help would be appreciated - especially anyway who has dealt with this before? Cheers, Callum.

Hi,
This would be classed as self employment and you would need to convert the income to sterling. You can see guidance here: 
Set up as a sole trader: step by step
Thank you.