Probate, Will and Trust mentioned in Will in TN

Will left with mention to a trust for 2 minor children receiving real property when the youngest child reaches age 25 with no other provisions or instruction. Does the will serve as the trust or should the executor/trustee have a trust drafted as a second document? Does the executor/trustee have to file a petition with the court for approval to sale of property, to divide funds up into two separate bank accounts for children? Probate has not closed yet and property has not changed title yet. Admin Letters and appointment has taken place. One of the minors will be 18 in 2 years, does trustee have to get court approval every time funds are withdrawn from the trust account (bank account/market account) for college, medical, support and maintenance?