There are many ways to teach digraphs. My favorite way introduces digraphs with hand motions. Teaching with multiple modalities ensures you reach more students. When I introduce the "H Brothers" I use the story and motions from the Project Read program. Each brother has a story to help students remember the motions. The "CH brother" is the brother who likes choo-choo trains so students makes a motion with their arms like train wheels while saying "ch, ch, ch".
Each day during circle time, I read a different story that has a "ch" word in the title. Before I read the story, I introduce vocabulary words from the story. We discuss different meanings the words might have. When we come to words in the story with multiple meanings, we discuss how the word was used in the story. Doing this is helpful for all students, especially your ESL students. We also listen for words with "ch". When students hear a word with "ch" they (quietly) make the hand motion. Another activity that enforces "ch" is to put the vocabulary words in a pocket chart and then mask the "ch" in words. To make a mask, I cut up colored folders that you can see through.
There is also additional practice with extension worksheets and literacy centers in my All Star Digraphs. One of my favorites is to type up sentences from the story I just read to the class. Print the sentences on cardstock and cut apart words like puzzle pieces. I like to use those scissors you find in the scrapbooking aisle that make pretty edges. The sentences are self checking. After awhile students will figure out tricks like real puzzles. You know how you begin a jigsaw puzzle with corners or straight edges. With sentence puzzles, students will soon learn that the first word with begin with a capital letter and the last word will end with a punctuation mark. This activity reinforces writing conventions and reading. Two for the price of one!
Here's the packet I made. It's available on TPT for $5.
These are the books that I used when I wrote the lessons for this packet: