Becoming a skilled reader is a complex process, and children need to build skills in a variety of areas, specifically their oral language/language comprehension (understanding) skills, and their word recognition (decoding/reading) skills.
This graphic shows how the 5 key components of reading are related to word recognition and language comprehension, and how these two skill sets work together to allow for skilled reading.
BOTH sides of this simple view must be supported to help children learn to read and spell.
Phonological Awareness is an umbrella term that includes the awareness of the larger parts of spoken language, such as words, syllables, and onsets and rimes - as well as the smaller parts, phonemes or sounds.
Phonemic Awareness is a set of phonological awareness and includes the ability to identify, isolate, and manipulate phonemes in spoken words. These are sound level activities. Phonemic Awareness is the most important part of phonological awareness for reading and writing.