Christadelphians do not believe in the Trinity.
The doctrine of the ‘trinity’ is not found in the Bible.
Neither does the doctrine make any sense. - it is declared to be 'incomprehensible' by those who profess it.
The doctrine was invented by the Church which fell into apostasy and went on to become the 'Mother of Harlots' described in Revelation 17.
Her 'daughters' are those 'Churches' which teach the same false doctrine.
May I suggest that you read:
One God or a Trinity? https://www.thisisyourbible.com/library/show/1036
Jesus: God the Son or Son of God? https://www.thisisyourbible.com/library/show/169
I hope this helps.