Hi just a question I need answered

My daughter had a visiting author at school yesterday...

Her tips on getting published was to enter as many competitions as
possible. Because publishers have two piles for MS when they receive
them...one for published authors and ones who have won awards and
the other pile is for those who have nothing published or have won
no awards.

So Should I now enter competitions...Or can I submit part of my
story in these competions...to save me the time(which I find hard to
find) to write something else like a short story which I hate doing.

Does submitting a part of my story interfere with it being
published. Because I have seen a competition where you can enter the
first 5,000 words of your childrens MS....

Would love some feetback
Maureen