Notice that they had to cross the river to follow the compass southward. This means they had been camped on the north side of the river. Nephi makes a point of the fact that they brought with them seeds of every kind. These were various grains, vegetable seeds and fruit seeds they had brought with them from Jerusalem. This little company did not know it but they were launching into a journey of over 2,500 miles that would last 8 years. They would ultimately cross the entire Saudi Arabian desert. In volume one of Treasures from the Book of Mormon on page 24 there is a map outlining the trek of 2,500 miles across Saudi Arabia which Lehi and his family followed.