"So (including the other reply) if the adjective is in front of the noun it means that it refers just to that and I can add is,are.. (in my head, so I can understand at the beginning)? So this is how we know that farmer was smart farmer and not happy farmer? The one in front defines what is the subject, and the last adjective defines what is happening to it - he was happy?"

Thatʻs right. When "adjectives" are used as adjectives, theyʻre placed after the noun they refer to, much like in the romance languages. If you place them BEFORE the noun theyʻre describing, they essentially become descriptive verbs. (Though again, even trying to describe them using European "parts of speech" isnʻt quite right.)

"Also with ke Ua and ua - if it's ke, ka, na (plural) in in front does the verb always changes to a noun? Just started so don't have words for example, but like ke snow, snowing, ke knitter, knitting, ke car, driving (at this point have a break for a proper laugh)"

I donʻt know if I could go so far as to say "always", but essentially yes. Or, maybe more accurately, if you take a word (which out of context can often be several different parts of speech) and add a "noun marker" to it, such as "ka/ke, nā, he, ʻo, koʻu/kou/kona..." then youʻve signalled that youʻre using the word as a noun.

Tenses of verbs are signalled by particles. Some of these come before the "verb", and some come in two part before and after the "verb". But there is no inflection for conjugation or tenses.

As Douglas Julian said tenses of verbs are signaled with particles so a simple case : Ke 'ai nei au I eat. I 'ai au I ate