Complex sentence: According to Tait, Smith was planning to set up an opposition research company and claimed that Flynn, Kellyanne Conway, Steve Bannon, and other campaign advisors were coordinating with him "to the extent permitted as an independent expenditure".
Split into simpler sentences: According to Tait, Smith planned to set up an opposition research company and cited the Trump campaign as one of the four groups involved in the project. A document describing his plans claimed that Flynn, Kellyanne Conway, Steve Bannon, and other campaign advisors were coordinating with him "to the extent permitted as an independent expenditure".