The Dative case (additive) answers the questions КЕМГЕ? (to whom?/for whom?), НЕГЕ (to what?/for what), КАЙДААР? (where to?).
To form the dative case you need to add one of the affixes -ГА, -ГЕ, -ГО, -ГӦ in сase the base of the noun ends in a vowel or voiced consonant like (й, л, м, н, ҥ, р).

When you see a noun base ends in a voiceless consonant like (к, п, с, т, ф, х, ч, ш, щ) you add the affix beginning with the voiceless consonant too –КА, -КЕ, -КО, -КӦ.

Follow the Vowel harmony rules to define which vowel shoul be in the affix:
if you see in the last syllable one of the soft vowel sounds (и, е, ӱ) you take affix –ГЕ or –КЕ, for example: Эзенгеto Ezen/for Ezen, Чейнешкеto Cheinesh.
Add -ГӦ, -КӦ after the vowel (ӧ) in the last syllable, for example: ӧртӧккӧto a duck, тӧртӧнгӧto forty.
And finally after the hard vowels (а, ы, у) in the last syllable you have to take -ГА, -КА: улускаto people, айугаto a bear, алыпкаto an athlete, каскаto a goose.
Add –ГО, -КО after the (o): койонгоto a hare, олоргоto them/for them, тошкоto ice, Торкогоto Torko (girl’s name).

Don’t forget that the Dative case is also the Additive that answers the questions КАЙДААР? (WHERE?) indicating the place and destination of movement (to, towards) мылчагаto the sauna/ for the sauna, школгоto school/for school.
Кем магазинге барар? – Who will go to the shop?

Also it answers the question WHAT FOR? FOR WHOM? indicating the reason of movement (because of ). For example, балаchild, балагаto a child/ to take the child, мен детсадка балага келдимI came to the kindergarten to take the child home.
Калашbread. Калашка акча береерGive me some money to buy the bread/ give some money for the bread.
Тонcoat, тонгоfor a coat. Кара тонго кара топчы экелbring a black button for the black coat.

Personal pronouns in dative

Nominative Dative
мен I меге to me/for me
сен you сеге to you/for you
ол he/she/it ого to him/to her/to it, etc
бис we биске to us/for us
слер you (pl)       слерге to you/for you
олор they олорго to them/for them

Note that pronouns МЕН, СЕН, ОЛ drop their last consonant in the position before the dative affixes: мегеto me, сегеto you, огоto him.