Hebrew Language/Meaning of roots
Where can meanings of roots be found. And why do roots have meanings since i thought that only when vowels are added do roots take on meanings.
You're correct in saying that the roots for themselves have no meaning, they are usually three-four letters that have to be put into "molds" to create words. However, the letters of verb-roots (this is not the case with noun-roots) form words which are verbs in the male + third-person + past form and usually do have a meaning.
As for finding the meaning of roots, a standard Hebrew dictionary is not based on roots (in contrary to Arabic dictionaries), but if you search for most roots in a "regular" Hebrew dictionary (such as http://www.morfix.co.il/
or Google Translate) you will most likely find the male third-person past word.
ש.מ.ע is the root forming many words, both verbs and nouns, such as שמיעה, לשמוע, שמועה, שמעתי etc., and the word שמע by itself means "[he] heard".
ק.ר.א is the root forming many words, both verbs and nouns, such as קריאה, קראנו, קוראים, מקראה etc., and the word קרא by itself means "[he] read".