1 it is the basic dictionary form of the noun, so no need to choose an ending
2 use for nouns endings with a hard consonant + -a in Nominative
3 use for nouns endings with a soft consonant + -a or a consonant in Nominative
4 use for nouns endings with -a in Nominative
5 use for nouns endings with a consonant in Nominative
6 both the Dative and Locative case have the same forms and rules of applying endings
7 there are some feminine nouns that end with -i, i.e. gospodyni, pani
8 some masculine nouns take the -a ending. To decline them use feminine endings in singular number, and masculine endings in plural number.
9 use for nouns ending with a consonant followed by -a excluding personal affectionate names with a soft consonant.
10 use for personal affectionate names that end with a soft consonant followed by -a
11 use for nouns ending with -i
12 use for nouns ending with a consonant