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):

-drop -re
-add -to

examples: dare (to give) = dato, mangiare (to eat) = mangiato, dormire (to sleep) = dormito.

for the second group (-ere verbs)
-drop -ere
-add -uto

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