Advice on renovating a damp/mouldy 1890s home

Has anyone been able to successfully renovate a prewar solid brick house with damp & mould problems and not had the mould return? Please could you share a step by step process of what you’ve done renovation wise I am looking to renovate a property with damp & mould problems but not sure how to go about it or where to start from.

Also has anyone added either external or internal wall insulation to their home and regretted it?

Thank you ☺️