You get a job, you save a deposit and find a flat or bedsit you can afford.
Most landlords require at least a deposit of 3 months' rent and one months' rent in advance.
Then you will need to pay gas, electric, possibly water rates, buy furniture, bedding, crockery, cutlery, saucepans (unless it is furnished). You will need to pay for your internet connection, assuming you have a pc.
It costs a lot of money to live away from the family home at 16 - the wages tend to be quite low.