Dynamic Actions Doubt

0007 STAT3 P P0007-STAT3='0'

0007 STAT3 P PSAVE-STAT3='1'

The step is taken if the value in the P0007-STAT3 field changes from 1 to 0.

HOW I cant undersatand?

Also ,

Could not understand this too ...

Infotype Field .... Ind. Variable function part

.... I INS,19,01/D

Step: Create a Dates record, subtype 01, run in the background

.... I DEL,14,M559

Step: Delete Rec. Payments/Deds. record with subtype (wage type) M559.

0007 .... I INS,8,,,(P0007-BEGDA),(P0007-ENDDA

M stuck please help !

Cant understand Dynamic Action...