Verbs come in two flavours, regular and irregular. If a verb is regular the past simple and the past
participle end in 'ed' - for example:
Infinitive: Clean finish use paint stop carry
Past simple: Cleaned finished used painted stopped carried
Past participle: Cleaned finished used painted stopped carried
we use the past participle to make the perfect tenses and for all passive forms.
Perfect tenses: (have/has/had cleaned)
I have cleaned the windows (pres perfect.)
They were still working. They hadn't finished. (past perfect).
Passive: (is cleaned/was cleaned etc.)
He was carried out of the room (past simple passive)
This gate has just been painted. (pres perfect passive.)
When the past simple/past part do not end in 'ed', (for example: I saw/I have seen) then the verb is
With some irregular verbs all three forms - infinitive, past simple and past participle are the same - example, hit
With others the past simple is the same as the past participle but different from the infinitive: example, tell/told.
Last, with some others, all three forms are different: example, wake/woke, woken.
Some verbs can be both regular and irregular. There are 8 of them: burn, dream, lean, learn, smell, spell, spill and spoil. They can be stated thus: burn: burned or burnt. In British English, the irregular form is more usual.
Do not be afraid of irregular verbs. There are far fewer of them than you might think, given the enormous number of words in the English language. In fact I have a list, and there are only 116 of them. That means they are easy to learn - at first you will have to consult a reference book, after that, you will find that you have learned them. There are some native speakers who get them wrong, sadly, so reading cannot always be your guide. Also as usual, there are differences
between American English (Am. E) and British English (B.E). An example is lighted/lit. Americans don't use lit as “Daria lit the lamp” but always say lighted. “She lighted the lamp”. If you want to learn British English, and I presume that you do, or you would not be reading my blog, then be aware of what you read. Otherwise, my advice is as usual - read and listen, every chance you get.