Tips for cleaning a 40 year old house I just bought

Hey everyone,

I just purchased a house and won't be moving in for about a month, so I figured that while it is empty I would clean it as well as I could while it was empty. I will renovate it in the future but would like to clean it first.

I have some questions that I thought this sub would be able to help me with.

It was built about 40 years ago and an old man lived there on his own for about 10 years. It then sat empty for around 2 years so it has a lot of built up dirt and grime.

Some rooms have a thick build up of cigarette smoke, how would I clean this off the best?

I was thinking of using bleach on pretty much every surface, do you think this is sufficient?

I am thinking of using an ozone generator to remove odor. Is that a good idea? To get the best results, would it be better to use the generator before or after cleaning? There are no furnishings yet so don't have to worry about damaging anything like that.

Would you have any tips for cleaning things I might overlook?

Thank you for any help. I want to do it right the first time so I can move it to a nice new feeling place. I appreciate any insights.