Northern Yearly Meeting's Faith & Practice can be found here: https://www.fgcquaker.org/cloud/northern-yearly-meeting/pages/nym-faith-practice. You can purchase it as a hardback, a paperback, or download a free PDF.

The Quaker way emphasizes experience over religious belief or doctrine.  It is inherently difficult to capture the essence of that experience in words.  Yet every Faith and Practice attempts to do that very thing.  This Faith and Practice describes the beliefs of Friends and the structures and processes of Northern Yearly Meeting, and its Monthly Meetings and Worship Groups.  It also explains the spiritual foundation of these processes and of our way of worship. It should be of interest and value to newcomers and old-timers alike.  [from Pacific Yearly Meeting Faith & Practice web page]

Dearly beloved Friends, these things we do not lay upon you as a rule or form to walk by, but that all, with the measure of light which is pure and holy, may be guided: and so in the light walking and abiding, these may be fulfilled in the  Spirit, not from the letter, for the letter killeth, but the Spirit giveth life.

[advices from the elders at balby, 1656 britain yearly meeting quaker faith & practice, 1995, §1.01]