whole text translation and grammar point of 的and给
The 1st sentence really looks like consisting of 3 parts. 

小白兔回到家里，The white bunny returned home, 
种上了菜籽 grew vegetables
兔给白菜浇水 The bunny watered the plants.

给 in itself means to give, but in many cases, just as here, it is used as a "preposition" that marks the benefited person of an action. E.g.

我给你看看。 I show you/I let you have a look. ("I give you a look. ")
我给你带来了一本书。I brought you a book. ("I brought a book to give it to you.")

2nd sentence: 

兔把山羊送的白菜拿回家里。To understand this sentence, you need to take it apart. 

山羊送的白菜 means the cabbage that is/was presented by the goat as a present. It is a structure that has 4 parts:

(1) 山羊 the goat
(2) 送 to give (as a present) or to send
(3) 的 attribute particle
(4) 白菜 cabbage

The whole structure is constructed like this: WHO + ACTION + PARTICLE + OBJECT (affected by the action). E.g. 姐姐买的茶 the tea that was bought by elder sister. 

拿回 is another thing you need to learn, it is a verb with directional complement, it means take and return (home). A verb is essentially complemented by another verb to show the direction of the movement/action. 

There is really no point learning these particles and complements the hard way. Get a grammar reference and work yourself through the examples and the drills. It is a lot easier than trying to translate some easy looking sentence with a dictionary. It is too confusing the way you are trying to do this.  

3rd sentence:

他天天不干活儿，饿了就吃山羊送的白菜，白菜很快就吃完了。

He idled his days away, when he was hungry, he just dined on the cabbage given to him by the goat, and soon the cabbage was all eaten up. 

There was a wrong character in the 3rd sentence, I suppose it is 饿 not 饯.