ð is edh, it represents a voiced dental fricative, like the "th" in "them"

ŋ is eng, it represents a voiced velar nasal, like the "ng" in "sing"

ç is a "c with cedilla" or "broken c". It's used in several languages with different readings, but they seem to be using it as a voiceless aveolar affricate, like the "ch" in "match"