I need to change accounts on several checks and change amounts on deposits, how can I go about locating, opening, and editing them?
If posted, you can't edit them. Corrections would involve posting reversals and re-entry.
And there is no way to Unpost them? And is there a way that I can tell if they have been posted?
Sage 100 is not a spreadsheet like system. When you post something the data goes into read-only history tables (maintaining an audit trail of corrections by recording posted reversals and replacement transactions).
If the data you want to correct is not in a data entry screen (but showing up on the customer / vendor record...) then it is posted. GL only corrections can be done with a journal entry, but to affect module data (AR/AP...) you need to do what I indicated, with few exceptions. (AP Invoices can be adjusted without a reversal).
You unpost by reversing the checks. You can tell if they have been posted by going into the vendor and seeing if the check is listed.
*Community Hub is the new name for Sage City