Right component supplies the sound:
旨 zhǐ → zhǐ (exact match).
旨 itself depicts a spoon (
匕) over a sweet-mouth (
旨 = 'tasty essence'), and gives the abstract 'gist / aim' meaning. Combined with the hand it produces 'a hand pointing at the essence' — the literal picture behind
指示 (to indicate the gist) and
指点 (to point out).