Your first remesh

One minute, on the sample head.

1. Open the QuadGuide tab in the sidebar (N). With nothing selected the panel offers Add Sample Head: press it. Or select your own mesh in Object Mode.
2. Pick a Style:
   • Character: organic flow that follows the form, hard edges kept. The best start for most models.
   • Sculpt / Scan: the same for noisy or dense surfaces; only clear creases count as hard edges.
   • Hard Surface: CAD-like parts, sharp edges and flat panels.
3. Set Quads: about how many quads you want.
4. Press Remesh. A progress bar runs; Cancel (or Esc) stops it at once.

The result, <name>_quadmesh, appears in the original's place. The original is only hidden: Show Original (Shift+Q) switches between the two.

Bottom left of the viewport, the verdict says how it came out: clean: with the number of quads, poles and seconds, or what needs fixing. The panel's result card says the same, with what to do next: see The result.

Next

• Not the flow you want round the eyes? Your first guided remesh: draw a loop there and Remesh again.
• Quads too big on the face, too small on the back? Paint density.
• One area wrong? Select its faces in Edit Mode and use Remesh Selected Faces.