You can do basic celestial navigation without the need for the sextant or charts and books. It will not give you a precise latitude or longitude, but if you are not completely unfamiliar with the area you are in, it can keep you oriented and going in the right direction. There are many books and videos on the subject:

Finding Your Way Without Map and Compass

Natural Navigator

These books include many other techniques than just celestial navigation as well.

Ron Hood (RIP) has some useful techniques on video:

Primitive Navigation

The sextant and charts method is interesting, and not a bad thing to know, just difficult, resource intensive, and dependent on on a clear sky.