Complex sentence: It was published as a bi-monthly companion book to fill in the gaps of continuity in the TMNT universe, therefore making Eastman and Laird's Teenage Mutant Ninja Turtles and Tales of the Teenage Mutant Ninja Turtles in the same time continuity, and canon to each other.
Split into simpler sentences: It was published as a bi-monthly companion book to fill in the gaps of continuity in the TMNT universe. Therefore, making Eastman and Laird's Teenage Mutant Ninja Turtles and Tales of the Teenage Mutant Ninja Turtles in the same time continuity, and are canon to each other.