Renting an Apartment in Rome for the First time

Hello Everybody!

My name is John, I'm from the UK, and from March 2020, Will be the first time ever, that I move abroad to Live and Work.
I just want to ask for some Advice for People who have Experience in Moving and working in Italy.

I have a Few questions regarding Renting an Apartment in Rome. I have been looking at several apartments in Rome On the Internet, but One thing I do want to ask is that, For example, I have seen an Apartment which is Outside the Central area of Rome for 700 Euros, but I also see the Square (M2) bit.
Now with the M2 bit, It says about let's say 10 Euros per M2. So this place is 10 M2. If I see an Apartment for  700 Euros and let's say the flat 10M2, Does that mean I would have to pay an additional 100 Euros on top of the rent?

Just One More Question, I tend to live in Rome for the rest of my life, Do I need an apartment first and then apply to be a Resident, or do I have to apply to be a resident first and then find a place to live?

Thank you for your time and I hope I haven't confused anybody!