However for a layman, DTA/DTL are your assets or liabilities of Income Tax you have saved or have to pay in near future, because of different accounting policy as per you and Income Tax Act.
It can be estimated by multipling the applicable tax rate of your Profit as per PL with you accounting policies followed, and Net Taxable Income as per Income Tax Act.
This is created on Timing Difference which have arised due to different policies followed.
For further please go through AS - 22, or ask a specific Question with Facts.