Knitting into the front loops is the normal procedure and is used unless otherwise specified. Knitting through the back loop twists the stitch. 

Knitting Into the Front Loop 


Insert the right needle into the front of the stitch from front to back and continue to knit the stitch. 

Knitting Into the Back Loop 


Insert the right needle into the back of the stitch from the front to back and continue to knit each stitch.