1) Check out Wikiversity on the 1st declension.
2) 2nd declension nouns can be masculine AUT neuter in gender (see Chapter 3 in our libro). The nominative singular masculine has -US as the ending and the nominative singular neuter has _UM as the ending. (There are also a few masculine nouns with -ER as the ending.) These are the endings for all the cases; you don’t have to know these yet.)
3) Be ready for an in-class listening/vocabulary exercise Wednesday: I’ll read a list of words and you’ll need to note if they are feminine, masculine, or neuter (for chapters 1-3). You should be familiar with the words but if you don’t have time to learn all the meanings, that is all right.
There will be a quiz on declining the first declension and translating on Thursday.