Signatures on Separation Agreement

Can you tell me if both parties have to go together to have the separation agreement signed before the notary? or can we go to separate places and have them notized separately?

Also just to make sure I understand correctly- the sentence below which is on my agreement states the following:

IN WITNESS WHEREOF, the parties have set their hands and seals to this agreement in duplicate, one copy which is retained be each of the parties, the day and year first above written.

So this mean we make 2 copies of the agreement- have them both notorized and each keep a copy with orginial signatures? correct?

It is not necessary for both parties to sign the agreement at the same time.

Yes, the language you quote means that two originals of the agreement shall be executed with each of you keeping one.