For absolute beginners, there are resources on the net such as these
ESL kids video slides and lots of
worksheets and
flashcards to go with them. Everything is arranged according to students' levels. The worksheets will help with things like handwriting and phonics because if they are very young you want to develop their motor skills. Flashcards can be used to present and practice new language.
Of course you should teach basic communicative phrases like "Hello", "How are you?" alongside alphabet and phonics. Do not wait until they have master phonics and alphabet before teaching them basic dialogues. SONGS help a lot. I sing most of the language into their little brains with some actions. Let them do something as they sing - mime an action and so on. A popular song like "If you are happy and you know it clap your hands." is good for provoking a physical response. You sing and they do the actions- Don't worry they will copy your actions very fast. Children learn faster that way. Coloring activities and so on will help to teach vocabulary.
Games add fun to lessons. Games could simply be listening games like SLAP and SAY.
Put pictures on the floor and say something like: "A for Apple" They slam the apple card and repeat.