[general statement]。具体来说,+ [details]
具体来说 introduces the details behind a general statement: what exactly, how many, which ones. It comes after the general point and opens the next sentence, followed by a comma.
具体地说 means the same. 具体而言 is the written form, at home in reports and essays; 具体来讲 is a spoken variant.
The same frame gives a set of openers that position what comes next: 一般来说 "generally", 总的来说 "overall", 简单来说 "in short". 具体来说 is the one that zooms in.
The general statement comes first. 具体来说 opening a text, or leading into something vaguer, reads backwards.
The frame takes no 的.