The first chapters of the Yoga Sutras dive into this. Reading multiple translations and commentaries on this can be helpful. In this article, I tried to document A.G. Mohan's view.
Literally means "proof" and "means of knowledge". For now we call it 'correct knowledge' Many translations done by Western people see this as the ultimate goal, probably because today's scientific paradigm was fueled by it. However Patanjali clearly mentions that Pramana,Vikalpa and Viparyaya are disturbances (vrittis) of the mind.
Vikalpa is a tricky one. In short:
See here for an indepth article.
Needless to say, this is just an example. In general it's good to have some survival-insticts and reflexes.
As seen in the last picture, Sankalpa is imagination (a mental picture) and a mental resolution/command in one thought. One could imagine it like a picture which has the filename 'jump now.JPG'.
The message of the Upanishads Sutras (which the YS are based on) is :
Root out sankalpa in wordly desires
Watch this excellent video by A.G. Mohan :