How do I get a bank account report for a specific period
That depends on what you want the report to include. One method to drill down on either the cleared or actual balance in the Bank and Cash Accounts tab, then copy to a spreadsheet and manipulate as desired.
Another is to create a Bank Account Summary report in the Reports tab.
Or you might need a custom report.
Again, all depends on what you want in the report.
Of course, the easiest thing might be to obtain a statement from your bank.