Membership units, % ownership

I'm working on my LLC Operating agreement and I don't know how to determine the "membership Units" for my company. Do I need to specify this number on the LLC Operating agreement?

Also, I will appreciate if you can help me to Clarify the "% Ownership"

Thanks,

100 percent exists so if each party gives 20 dollars to the capital of the company, and five parties exist, then each has 20% unless you agree otherwise.

...and so on...

Membership Interest: A member's ownership interest in the LLC is called a membership interest. Membership interests are often divided into standardized units which, in turn, are often called shares. Unless otherwise provided for in the operating agreement, a member's right to control or manage the LLC is proportionate to their membership interest.