Holding the cube, AUF and rotations

Why an algorithm has a 'front', what AUF means, and when to rotate.
Algorithms assume you hold the cube a certain way: for last-layer cases the solved part is on the bottom and the case must be turned to match the diagram before you start. Turning the top layer to line the case up is called AUF (adjust U face). Algorithms here are checked with that freedom: where an alg needs a different AUF than the diagram shows, the case page tells you which (for example 'AUF U2').
Sune as drawn on this site.
Checked by the engine: OLL OLL 27
The same case, turned: do U first (the AUF), then the same algorithm (the checked moves are below).
Checked by the engine: U R U R' U R U2 R' → oll-solved
R' U' R U' R' U2 R y U'
The last step usually ends with an AUF too: PLL algorithms finish with the top layer up to a quarter turn off. Rotations (x, y, z) are free in state but cost time; many algorithms have rotationless versions, tagged 'rotationless' on the case pages.
Colour schemes: diagrams follow the standard scheme with white on the bottom and yellow on top for last-layer cases, as most solvers hold the cube for CFOP. The algorithms do not depend on colours.