How do you make a Humanoid go to another humanoid that is not a player?

You could use something called WalkToPart or WalkToPoint. WalkToPart is an object value so make the WalkToPart the enemy's torso or something like this:

game.Workspace.Player1.Humanoid.WalkToPart = game.Workspace.Enemy.Torso

The character will walk to the enemy.

This would also work. This uses WalkToPoint which is a Vector3 value.

game.Workspace.Player1.Humanoid.WalkToPoint = game.Workspace.Enemy.Torso.Position

I hoped this helped! Below is some EXTRA STUFF YOU MIGHT WANT TO KNOW!

With this feature has some drawbacks. If it's a player then they can just WALKAWAY! What you might want to do is make a loop that loops until the humanoid has reached it's destination.

while wait() do
    game.Workspace.Player1.Humanoid.WalkToPoint = game.Workspace.Enemy.Torso.Position
end
--or
while wait() do
    game.Workspace.Player1.Humanoid.WalkToPoint = game.Workspace.Enemy.Torso.Position
end

Note this will make the player go on forever and when the enemy dies or dissapears, then the script will error so work this out.