The ancients learned nothing,

Young people never grow old.

What you get on paper is superficial,

Never knew it needed doing.

(Yu Zi is the son of Lu You)

Word translation:

The ancients (predecessors) had no (no) legacy (residual) strength (strength) in learning.

Young people (when young) work hard (hard work), old people (success, achievement).

I feel (feel) shallow (superficial) on paper (book).

Never (completely, thoroughly) know (know, understand) this (this) thing (reason, reason) and do it yourself.

Free translation:

This poem means that the ancients spared no effort in learning. Fight for it all your life, often when you are young, you will succeed when you are old. The knowledge gained from books is superficial after all, and it is impossible to understand the true meaning of knowledge. To truly understand the profound truth in books, you must practice it yourself.