Hi @sujanaab
Can you please have look into this [post] , and it has clear examples of calculating different period based measures. (Period Over Period and Other Date Comparison Calculations (YoY, MoM, YTD, Rolling 90 days, etc))
In QuickSight every period calculation YTD/MoM/Prev-Month will be considered as separate metric and it gets computed based on the dimension & date field grouping .
For further support would recommend to upload sample data in Arena , and share with us your progress.