regarding TDS

You have already obtained TAN. So, you can deduct TDS u/s. 194C from the payment to contractor, when exceeded the threshold limit (this deduction is under Income tax act).

As such you (being Individual or firm) are not liable to deduct TDS under GST..... even than the TDS deduction under GST is postpond till next April. (for all eligible deductors)

So chill.........