I don't think I could tell you a whole lot about this subject other than the fact that using these forms sounds extremely formal at best. (with some exceptions - some verbs used in this form of the passive voice in certain contexts - of course, but I can't think of any at the moment)
"Adaték" means "was given" (it could be either a first person singular or a third person singular form but the former seems unlikely). "Megadaték (in formal Modern Hungarian you'd have "megadatott" but I wouldn't be that shocked if this somewhat more archaic form was given way to instead) neki a lehetőség, hogy..." "He was given the opportunity to..." (lit. Was given to him the opportunity, that...)
adatni - to be given (adni - to give)
adatok - I am given (which to me doesn't make a lot of sense since this is not something I would say about a human being and even if I were to do that I wouldn't use this somewhat archaic form)
adatsz - you are given (keep in mind that we're talking about passivization of direct objects, ie. this can only mean you are given TO someone or something and not under any circumstances you are given SOMETHING or SOMEONE; I can't however think of a single context where I could conceivably use this form without being subjected to ridicule; which actually means there is a certain set of contexts where it COULD be used for a desired facetious effect - comedy)
adatik - he/she/it is given
(Again, I would mostly only ever use the third person singular.)
adattam/adaték (with the latter being archaic but even so perhaps more in use, however marginal the extent of that may be, than the "modern" form which is highly unusual whereas I wouldn't be that surprised to see the archaic form in an older text or one that tries to look and feel like one)
For the future you just use the auxiliary "fog" (I'm reluctant to write "fogni" since that sounds extremely alien to my ears since the infinitive suffix in this case is always attached to the main verb, eg. he/she/it will help - segíteNI fog)
But I cannot stress enough how out of use most, if not all of these verbal forms are.
Hope this helped.