Masculine nouns with -o change to -i (il ragazzo = i ragazzi). Feminine nouns with -a change to -e (la ragazza = le ragazze). Gli is the plural for l' and lo (l'uomo = gli uomini)
However, there are some masculine singular words ending with -e. Like"il pesce" or "il giornale". But I miss this in the explanation which I copy paste above.
If you type giornale into the Italian wikipedia you'll get an article about newspapers. But translating giornale as journal could be correct in some situations.
Depending on what you mean by "journal", the appropriate Italian word could be diario, rivista, quaderno, libro giornale, or something else.