This Italic text tense is like the third form of the verbs in English (done, fallen...), and is used only to compose some other tenses like passato prossimo, trapassato prossimo/remoto, congiuntivo trapassato.
A general rule to form the Participio passato (not valid for the irregular verbs) is the following
for the first and the third group (-are and -ire verbs):
examples: dare (to give) = dato, mangiare (to eat) = mangiato, dormire (to sleep) = dormito.
for the second group (-ere verbs)
cadere (to fall) = caduto; avere (to have) = avuto
Remember that for the verbs in which -ere follows -sc (conoscere (to know)), the sound sh must be preserved also in the participio passato form, so an -i must be added in front of -uto:
conoscere = conosciuto
some irregular verbs:
essere (to be) = stato