with Ada.Numerics.Discrete_Random;
...

subtype Faces is Positive range 1 .. 20;

package RandInt is new
  Ada.Numerics.Discrete_Random(Result_Subtype => Faces);
-- package RandInt is new
  Ada.Numerics.Discrete_Random(Faces);
   -- Creates a custom object-package
-- use RandInt; --?
...

Dice: RandInt.Generator;
Face: Faces:= 1;
...
Randint.Reset(Dice);
Randint.Reset( Gen => Dice);
Face:= Randint.Random(Gen => Dice);
Face:= Randint.Random(Dice);

 subtype Values is Natural range 10..50;
 package Random_Values is new  Ada.Numerics.Discrete_Random(Result_Subtype => Random_Values);

 Dice: Random_Values.Generator;
begin
 Random_Values.Reset(Gen => Dice);
 
 return Natural(Random_Values.Random(Gen => Dice));

 Seed: Ada.Numerics.Float_Random.Generator;
begin
 Ada.Numerics.Float_Random.Reset(Seed);
 
 return ( Ada.Numerics.Float_Random.Random(Seed) );
 -- in the range 0.0 .. 1.0

Discrete random

-- die roll simulation

WITH Text_IO; USE Text_IO;
with ada.Integer_Text_IO; USE ada.Integer_Text_IO;
with Ada.Numerics.Discrete_Random;

procedure DieRoll is
   subtype DieT is Integer range 1 .. 6;
   package Random_Die is new Ada.Numerics.Discrete_Random (DieT);
   use Random_Die;
   G : Generator;
   Die : DieT;
begin
   Reset (G);  -- Start the generator in a unique state in each run
   -- Roll a die
   Die := Random(G);
   put("You rolled a "); put(Die, 1); new_line;
end DieRoll;