First verb :)
So verbs are negated with لا, and other words are negated with لَيْسَ ?
I've also heard people use "ma" and "mesh" for negation, are they all interchangeable?
Má can be indeed Arabic and used in specific locations, but "mesh" is egyptian (and maybe some few others use it) and it is not pure Arabic at all.
Verbs in the present tense are negated with "lá" (لا). The article (Laysa: ليس) is not used with verbs, but mostly before nouns and semi-phrases (preposition+noun for example).
Also, the negation particle for the past is (lam:لم) which is added to the present tense to negate that verb in the past. As for the future, that's (Lan: لن), also added to the present tense to negate for the future. Examples:
He did not go: لم يذهب (lam yadh-hab).
He does not go: لا يذهب (lá yadh-hab).
He will not go: لن يذهب (lan yadh-hab).