Axle stands (where do I put them, Datsun sunny)

The short and somewhat unhelpful answer is, wherever the manual says that you can do so.

The more useful answer is, under major bits of chassis structure. On cars without a separate chassis, there is usually still some kind of strong box-section members running under there where you can put the axle stands. For a solid axle car, another good location is, fairly obviously, the rear axle. You can generally also find good solid body structure to place the stands on near any mounting points for suspension or crossmembers. Try to avoid anything which is single-skinned, like the floorpan or sills. Also avoid anything rusty-looking. Above all, when lowering the car onto the stands, go slowly and carefully so you can check that you're not crushing anything and that the car isn't going to slip off!