Other Incomes for Skilled Worker Tier 2 Visa

Hi, I am working in a company and I am a resident, have BRP, with Tier 2 Visa (Skilled Worker Visa). I am paying taxes my salary with the PAYE system. But I also have my own apps and earning from those apps. Not much yet but I want to learn should I pay taxes from earnings I do from Apple App Store and Google Play store from the things I sell within my apps like premium features. If I need to pay taxes from those earnings how? I am not able to be a "sole trader" or establish a company with tier 2 visa. Should I just enter my revenue to the HMRC system under the "other incomes" section? Best regards

Hi,
This would appear to be self employment, with tax and class 2 and class 4 liabilities.  
You should seek professional advice, to ensure that you are still within the terms of your visa.
Thank you