Fred and Donald Trump

I believe Fred Trump was in the single-family home construction business in Queens, New York. He later expanded into apartment construction, ownership, and management business.

I believe when Donald Trump graduated college his father gave him $1 million.

Did Fred also give him his construction, ownership, and management of the business?

Then Donald Trump went into real estate in Manhattan. Did his company build large buildings (e.g., hotels) there? Or did his company hire an unrelated construction business to build them?

Now Donald Trump is believed to be a billionaire. Is the incremental net worth from net profits over the years or otherwise?