get a grip

verb3

1. •
   To grip, as in: to take hold of, as with the hand.

   • I attempted to get a grip in the snow with my frozen fingers, to stem myself with my heels, but with no success, […] — 1898
2. •
   To come to one's senses and become more rational after having experienced a strong emotion.

   • He needs to get a grip if he's getting that angry over such a little thing.
3. •
   To attain the understanding of a complex topic.

   • […] the great antiquarian, Duald MacFirbis […], who was able to penetrate and get a grip of the long forgotten language of the ancient law tracts […] — 1913