(RH tutorial here)1. Before a Late Color Change, on an increasing angle, carry second color of yarn under last stitch in first color. This pulls the new color up to the same position as it would be in Tapestry Crochet, ready to pick up for next stitch.
2. Complete last stitch in first color for Late Color Change before dropping first color to back of your work, ready to pick up on your way back on the next row.
3. Pull carried yarn tight to hide it under stitches. Then use this yarn to complete the first stitch in the new color, with the old color on the top loop of the stitch.
4. For Chunky Weight Yarn Only: When working back in other direction insert hook under carried yarn and front loop only (flo) of Late Color Change.
This last step avoids holes in fabric with chunky weight yarns (as used in the Happy Day Playmat), but I have discovered, is not necessary with worsted or lighter weights. For lighter yarns insert under carried yarn and both loops.
As a left-handed crocheter, I always try to provide my tutorials for both right and lefties. Afterall, I take all my photos left-handed, and actually have to flip them for the right-handed version. Some of my testers are left-handed as well, and I know they appreciate a version with left-handed photos. Enjoy!