If you are starting to revise for your first MCA deck oral examination you may find the breadth of subject matter overwhelming. The following is a recommended reading list.
MGN 315 Keeping a Safe Navigational Watch
MGN 364 Traffic Separation Schemes
MGN 369 Navigation in Restricted Visibility
MGN 379 Use of Electronic Navigation Aids
SOLAS Chapter V. Annex 24 – Voyage Planning
NP100 Mariners Handbook 10th Ed – 2015 (May be ordered from here)
DO NOT waste time reading primers and websites if they do not have an official stamp MCA, IMO etc.
Ensure that any guidance you seek is from a reputable source. Contact me if you have any concerns and want to get some guidance.