How do form the past and past participle?

Answer 1

You form the past tense of regular verbs by adding -ed. The past tense of regular verbs is also the same form used for the past participle.

Irregular verbs don't add -ed to form the past tense but rather the word changes. For example 'eat' becomes 'ate'.

and

the past participle for irregular verbs is often a different word (or it can be the same as the past)

for example:

eat / ate /eaten - eaten is the past participle.

dig / dug / dug - dug is past participle.

run / ran / run - run is the past participle

Because they are irregular verbs there is no rule how to form the PP you just have to learn them.

Answer 2

To form the past tense, you usually add "-ed" to the base form of regular verbs. For irregular verbs, the past tense form varies—there is no set rule. To form the past participle, you also typically add "-ed" to regular verbs and irregular verbs have unique forms, like "broken" for "break" or "gone" for "go".