Sachet v/s Specific Intention - kya difference?

Yaar samajh nahi aaya, I've been grinding for CUET PG Law and still, these two concepts are giving me sleepless nights. In the context of Indian Evidence Act, 1872 and BSA, I'm getting confused between sachet v/s specific intention. I've been reading the sections (Section 6 and 12) but somehow, they're just blurring into one another. Sachet (or rather specific acts) is supposed to refer to individual acts performed by an accused, whereas specific intention implies that the accused had a prior intention to commit a particular act. But how to distinguish these? I've seen some examples where the courts have deemed the accused's actions as a specific act, but in hindsight, it seems like specific intention was the underlying motive. Please help, yeh confusion bahut dil se khatre mein hai!