Portuguese Grammar/Verb

The three conjugations
The verbs in portuguese have three conjugations:

The first (-ar), the second (- er*) and the third (-ir).

The conjugation suffix is ever the tonic syllable.

*The verb pôr is the revised form of the extincted poer.

Indicativ/Indicativo (In.di.ca.ti.vo)
A fact.

I walk.
 * Eu ando.

The subject certainly walks.

Conjunctive/Subjuntivo (Sub.jun.ti.vo)
It is uncertain.

If I walk...
 * Se eu andar...

The "if" shows uncertainly.

I hoped to walk.
 * Eu esperava andar.

It's a wish, so, it isn't certainly.

When I want, I will walk.
 * Quando eu quiser, eu vou andar. or (Quando eu quiser, eu irei andar. or Quando eu quiser, eu andarei.)

It' s more complicated to explain. When it has a relative pronoun, that is generally used to ask an explanation to the doubt of the first person, the conjunctive comes.

Maybe I walk...
 * Talvez eu ande...

Maybe I will walk.
 * Talvez eu vá andar. or (Talvez eu irei andar. or Talvez eu andarei.)

The "will" puts the action into the future.

He doesn't know if he will walk or no.
 * Ele não sabe se (ele) vai andar ou não. or (Ele não sabe se (ele) irá andar ou não. or Ele não sabe se (ele) andará ou não.)

Imperative/Imperativo (Im.pe.ra.ti.vo)
It shows a supposition to what the first person do to another person do.

Let's walk there.
 * Andemos para lá or Vamos andar para lá.

The first person is supposing to the other person that is with himself.

Walk two times a week in the beach and you will lose your weight.
 * Anda duas vezes por semana na praia e perderás o teu peso ou Anda duas vezes por semana na praia e perderás teu peso

The first person is indicating to the second what he should do.

'''Don' t walk! You are prohibited!'''
 * Não andes! Estás proibido!

The first person in forcing the second to don' t walk.

Conditional/Condicional (Con.di.ci:o.nal)
It shows what was in the subjunctive if the conjunctive come certainly, a hypothesis.

If you were fat, you would have to walk
 * Se fosses gordo, precisarias de andar.

Be careful!
If by 2030 you are fat, you will have to walk
 * Se em 2030 fores gordo, terás de andar.

It isn't a hypothesis, because the grammar future is uncertainly, the second person can be fat or not.

Nominal form(s)/Forma(s) nomina(l/is) (For.mas no.mi.nais)
It isn' t really a mood. It is the different forms that the verb can appear.