I'm a Language's student at the UFC in Brazil and I would like more informations and detals about: the "cases" of the Irish Language and Verbal Conjugation (Are there more Verbal Times or only this: Present, Past and Future?). I want to know about Possessive Pronouns.

The Irish noun could be said to have four cases.
1. The basic, or nominative-accusative, form, representing the subject, the direct object, &
also after certain prepositions, e.g "gan"

2. The prepositional, or dative, form, used after
the bulk of the prepositions.

3. The posessive, or genitive, form, expressing
possession, but also after certain
prepositions, like "trasna".

4. The vocative case, for addressing someone.

There are, excluding quite a few irregular items,
a very small number of patterns.
In virtually all nouns, the dative and the nom./acc. are identical, and in many the genitive is identical to them! The INITIAL mutations and the articles (when they occur)
express as much of the grammar
as the vestiges of the case endings.
Example of a "first-declension" noun:

an fear 'the man' fear 'a man'
don fhear 'to the man' do fhear 'to a man'
...an fhir 'the man's...' ...f(h)ir 'a man's...'
a fhir! 'O man!'

Note: The lenition of the "f" to "fh" has nothing
to do with the CASE of the noun, as such, but
is determined by the nature of the preceding
article. In "an chloch", for example, the nom/acc.
form for 'the stone', the initial C is lenited.
But this is because "an", when it means
"FEMININE singular definite article", triggers
the lenition. The occurrence of the lenition has
nothing to do with the case of the noun ITSELF.
"A stone, nominative", would be "cloch".
You can see how the articles, mutations and case
endings all interact to produce the total effect.

Sorry if I've made it worse...
See "Teach Yourself Irish" for the mutations
arranged in a tabular form.

As for the verbs:
For purposes of conjugation, the parts of the verb
are:
1) The verbal noun

2) The verbal adjective or "past participle"

3) The "conjugated" forms of the verb (8 "tenses")
INDICATIVE MOOD
i) The present tense
ii)a) The past habitual or imperfect tense
b) The past non-habitual or preterite tense
iii) The future tense
iv) The conditional tense
SUBJUNCTIVE MOOD
i) present tense- subj.
ii) past tense- subj.
IMPERATIVE MOOD
i) imperative "tense"

Aside from these "one-word" forms, there are
periphrastic forms using 'ta/', 'bi/m' in its
various tenses, the verbal noun, and the
verbal adjective, which express progressive
and perfective aspects. The Irish language is
EXTREMELY rich in terms of the nuances its
verb can express.

Unfortunately, a handful of verbs have so-called
"dependent" forms in some of their tenses when
they occur after conjunctions/particles.

e.g. "Ta/ se/ anseo." 'he's here'
but "An BHFUIL se/ anseo?" 'Is he here?',

where the interrogative particle 'an' "triggers"
the choice of the dependent form (As well as causing the eclipsis of the word).But these are
not separate "tenses" as such.
Each tense is also furnished with endings for
personal vs. impersonal and the personal forms
have endings for person and number.
HOWEVER...What was said above about nouns applies
equally to verbs. Several of the forms are
identical to one another. Again, it is the conText, and the surrounding particles and the initial mutations that do (or don't) occur that
carry much of the grammatical information.
By the way, other than the 11 or so irregular
verbs, there are only two verb conjugations
(with subclasses- no big deal).

As to the possessive pronouns, there are seven:

mo "my" lenites initial consonant
do "your sg." lenites initial consonant
a "his" lenites initial consonant
a "her" prefixes h to initial vowel
a/r "our" eclipses the following noun
bhur "your pl." eclipses the following noun
a "their" eclipses the following noun

Notice that they have differing effects on the
following word. This is how the words for "his",
"her", and "their" can be the same. Note that the
gender of the possesive pronoun has nothing to do
with the gender of the following noun, unlike, say
as in French.

examples: mo mhac 'my son' (lenition)
m' anam 'my soul'
do chroi/ 'your (sg.) heart (lenition)
d'anam or t'anam 'your (sg.) soul'
Note the dropping of the O when "mo" or "do"
occur directly before a vowel.

a anam 'his soul'
a chroi/ 'his heart' (lenition)
a hanam 'her soul' (h-prefixing)
a croi/ 'her heart' NO LENITION!!
a n-anam 'their soul' (ecl.)
a gcroi/ 'their heart' (ecl.)

a/r n-athair 'our father' (ecl.)
a/r gcuid 'our share' (ecl.)
bhur n-athair 'your father' (ecl.)
bhur gcuid 'your share' (ecl.)