For methods and the basic shape of the subject, start with Archaeology: Theories, Methods, and Practice by Colin Renfrew and Paul Bahn and Archaeology: A Very Short Introduction by Paul Bahn.
For wider subject range, The Human Past: World Prehistory and the Development of Human Societies gives a comparative world-prehistory survey, while Ancient Egypt: Anatomy of a Civilization and The Ancient Near East: A Very Short Introduction are useful for Egyptology and Assyriology interests.
For videos and talks, use Cambridge Archaeology for official course and research material, The British Museum for object-led museum explanations, and Archaeology Podcast Network for fieldwork and public-archaeology discussion.
For podcasts, The Archaeology Podcast Network Feed, The Archaeology Show and Tides of History help you build current examples and practise distinguishing evidence from speculation. Use Tides of History selectively for prehistory and deep-history episodes rather than as Cambridge-specific admissions guidance.
For structured online learning, Archaeology: From Dig to Lab and Beyond introduces excavation and lab work, Uncovering Roman Britain in Old Museum Collections uses Roman Britain and osteoarchaeology, Cambridge Subject Masterclasses gives official Cambridge subject exploration, and FutureLearn Archaeology Courses offers a wider course catalogue.