TC, Donald didn't build it. His dad built it. Donald has actually done a poor job of managing his assets. He should be much more wealthy if he had a clue.
When Fred Trump died he left a quarter billion dollar estate ($250,000,000). That estate was divided between his wife Mary Anne, and his children, sons Robert and Donald, and daughters Maryanne and Elizabeth. (Fred Jr. died in 1984.)
Each received about $35 million, after taxes.
But President Trump was in business long before his father died in 1999.
Fred gifted Donald with $1 million upon his graduation from college (as he did with all his children) which he used to start his own businesses. He was already a multi-millionaire when his father died, and had taken over the family businesses before his mother died in 2000 (his dad had been suffering from Alzheimer's disease for the past several years before his death).
And he turned that into over $10 billion. So much for "poor money management!" LOL!