Creating a plan from a baseline will copy periods-to-periods using fiscal year dates. You can select Auto Fill Plan Data to auto fill the last year of the baseline plan into the out years of the new plan. Note that the Auto Fill Plan Data option only appears if the new plan contains fiscal years that are not in the baseline plan and those fiscal years are after the start year of the baseline plan.
Contract line item details (Contract Type, Amount, Start Date, End Date, etc.) in the Contract tab should copy over to the new plan but the periodic amounts may be different based on the Start/End Dates and amortization method used.