There are several steps before you can win in a game of Teenpatti, the simple version is:
All of your cards should be arranged in proper sequences and sets
At least one pure sequence is required for a valid declaration
Select the card you want to remove and click on ‘Declare’ instead of Discard. You can also drag the card you want to declare to the centrally located DECLARE frame on the table in SBG PLAY Ludo.