If TDS/TCS is not calculating automatically in BUSY, Then follow the below steps.
Step 1: Make sure the TDS/TCS feature is enabled from the GST/VAT option from configuration under Administration.
Step 2: The TDS/TCS feature should be enable in the party master and set the applicability after limit.
Step 3: Mention the PAN number in the party master for calculating the correct TDS/TCS value.
Step 4: In the TDS/TCS bill sundry, the correct tds/tcs account should be tag and default value should be zero.
Step 5: In the TDS/TCS Bill sundry, The tds/tcs deduction amount should calculate either on net bill amount or taxable amount as per your requirement.