The site below and the PDF are pretty good resources.
To be clear a mortgage broker will facilitate the mortgage but they are not financial advisors so won't advise you on whether taking out that mortgage is right for you financially. In my experience they labour this a bit about getting independent financial advice, but for most people with a 'normal' income/savings just work out what you need to keep back in savings for an emergency, and what you can afford as a monthly payment and that's all the analysis you need.
https://www.moneysavingexpert.com/mortgages/mortgage-guide/