Isn't 'zu fuß gehen' translated as 'to walk' and 'gehen' to simply to go.
Ich gehe nach house = I'm going home. Ich gehe zu fuß nach house = I'm going home (by foot).
Or is it because a 'Woman and Man' are the subject of the sentence that it is implied that they are walking?
That's a simple question with a complicated answer. All of these mean "the," but are for the 3 grammatical genders in German. In the nominative case, where the noun is the subject of the sentence, it's "der" for masculine nouns, "die" for feminine, and "das" for neuter. "Die" is also "the" for the plural in any gender. Grammatical gender is sometimes logical, like "der Mann" or "die Frau," but sometimes not, like the diminuitive forms "das Mädchen" or "das Fräulein." Next is the accusative case, where the noun is a direct object of a verb or the object of certain prepositions. Then it is den-die-das for masculine -feminine-neuter. For the dative case (indirect object or object of other prepositions), it becomes "dem" for masculine, "der" for feminine, and "dem" again for neuter. Das Kind gibt dem Mädchen den Apfel = The child gives the girl the apple.
Okay so... Das is neuter die is plural and feminine and der is masculine. correct me if I'm wrong but den is used when the sentence is about the masculine object such as, er wascht den hund. Why isn't the sentence Die Frau und den Mann gehen? Because who is going? the woman and man, Man is masculine so therefore it is den man? I don't understand this? is it only used for objects?