Verbs have 3 forms: Infinitive, Past Simple, and Past Participle.
For regular verbs (ones that take -ed) the Past Simple and Past Participle are the same e.g.
Play > Played > Played
I play football. (Present Simple tense)
I played football yesterday. (Past Simple tense)
I have played football for years. (Present Perfect tense)
All regular verbs behave like this.
However Irregular verbs behave differently e.g.
See > Saw > Seen
I see the table is clean.
I saw the table was clean.
I have seen that the table is clean.
The verb Get is traditionally
Get > Got > Got
However equally valid in America and some other places is
Get > Got > Gotten
So the verb Get has two valid Past Participles.
I get dressed.
I got dressed.
I have gotten dressed.
OR
I have got dressed.
Both are perfectly legitimate.