Complex sentence: She explained that she had decided to contest the deputy leadership before hearing of Farron's resignation and that she had decided that the deputy leadership was the right role for her at the time; on 20 June, Swinson was elected unopposed as deputy leader.
Split into simpler sentences: She explained that she had decided to contest the deputy leadership before hearing of Farron's resignation and that she had decided that the deputy leadership was the right role for her at the time. On 20 June, Swinson was elected unopposed as deputy leader.