Learn Russian: Бедным пенсионерам очень нужна наша помощь.

In Russian, you express need by putting the person who needs something in the dative case. Literally, this sentence means that to the poor pensioners, our help is necessary. Since we are talking about multiple people, we use the dative plural endings: the adjective takes -ым to become бедным, and the noun takes -ам to become пенсионерам.

Why does the sentence use нужна instead of нужно or нужен?

The word for necessary or needed changes to match the gender and number of the thing that is needed, because that thing is actually the grammatical subject of the sentence. The thing needed here is помощь (help). Since помощь is a feminine noun, we must use the feminine form нужна.

How do I know that помощь is feminine? It just ends in a soft sign.

While nouns ending in a soft sign (-ь) can be either masculine or feminine, there is a helpful shortcut. Any Russian noun that ends in a hissing consonant plus a soft sign, like -шь, -чь, or -щь, is always feminine. Because помощь ends in -щь, it is guaranteed to be feminine.

Could I change the word order and say Наша помощь очень нужна бедным пенсионерам?