young people前边能用many吗

many young people是可以的。

people作为人们，是集体名词只有复数没有单数，所以可以用many修饰。

例如Many young people in our village are working in Shanghai. people作为民族讲有它的单复数。如，There are 56 peoples in China.

形容词修饰名词前后的顺序依次为“描绘/大小/形状/年龄（新旧）/颜色/国籍/材料+名词。

例如：

1、His father has three beautiful large round old white Chinese tea cups.

当然，在现实生活中我们很少这样说。我们任选几个形容词按照这样的顺序来修饰名词都可以。例如，1）He found a beautiful little square Garden.

2）He lost his little round American watch.