Blending is the process of saying the individual sounds in a word the running them together to make the word. For instance sounding out d-o-g and making dog. It is a technique every child will need to learn, and it improves with practice. To start with you should sound out the word and see if a child can hear it, giving the answer if necessary. Some children take longer than others to hear this. The sounds must be said quickly to hear the word. It is easier if the first sound is said slightly louder. Try little and often with words like b-u-s, t-o-p, c-a-t and h-e-n. There are lists of suitable words in The Phonics Handbook and the Jolly Phonics Word Book.
You can use the website link HERE to introduce blending - using the letter sounds we now know under "alphabet"
Click "Play" here for a tutorial on how to blend correctly