To give an overview of your talk in a presentation， you could say：

To give an overview of your talk in a presentation， you could say：
A.First of all， I'；ll go over some background details.
B.Then I'；ll look at...
C.After that， I'；ll move on to...
D.Finally， I'；ll review the main points.
正确答案：First of all， I'；ll go over some background details.Then I'；ll look at...After that， I'；ll move on to...Finally， I'；ll review the main points.