Payment Table option is located in Leasing Records > Purchase Contracts browser > Attached Records menu.
After populating necessary fields to generate lines in Payment Table window, The "Generate Payment Table" option located under the Operations menu is used to generate payment table lines.
 
The fields to populate in Payment Table are as below:

Payment Start Date

Payment start date refers to the start date on which rent payments will start after Leasing contract. This date value and period info generate rent installments. It is leasing record start date by default. It can be changed, however, new value cannot be a date that is older than Rent Start Date. If Payment Start Date and Rent Start Date are different, capital amount - down payment amount is calculated over the interest rate specified in the interest calculation parameter.

Rent Start Date

Rent Start Date value is taken from the Start Date in Leasing record and it cannot be changed. When a payment plan is calculated with Generate Payment Table, this date is transferred to the down payment line by default and it can be changed if needed.

Interest % (Yearly)

Refers to the interest rate applied for Leasing.

Number of Installments

The number of installments for Leasing rent payments.

VAT Rate

VAT rate over which Leasing payments will be paid.

Interest Type

While generating a payment table, installment can be generated by selecting Simple Interest or Compound Interest types.
If Simple Interest is selected, installment amounts are calculated by a simple interest calculation method.
If the payment start date is updated, then interest is calculated for the interval between Leasing Start Date and Rent Start Date and installment amounts are generated accordingly.
Amounts are calculated after changing the Interest Type using the Generate Payment Table option in Operations menu.

Period

It determines the relevant period in which Leasing rent payment will be made. It lists Daily, Monthly and Yearly options.

Insurance Amount 

The insurance amount of the leasing contract is specified in this field manually.  When the "Generate Payment Table" operation is performed, the insurance amount in the payment transaction lines is calculated with the "Insurance Amount/Installment Number" operation.

Down Payment Amount

It is the amount paid in advance for Leasing payment.