I really don't quite understand which part of the fantastic answer on the linked question you don't understand. I'll try to add some notes.
である is for all practical purposes a copula (like だ). This means in particular that your sentence structure will consist of a topic/subject and a predicating noun phrase.
The topics/subject may be marked by は/が/も; the predicating noun phrase is marked by である (for this example; generally だ, です, ...). Schematically,
A [は・が・も] B である。
You know that you can insert the topic/subject between で and ある for emphasis
B で A [は・が・も] ある
Note that this shortens the distance between the topic/subject and ある.
Other examples, which may be found on the internet
ご自身の責任で 完全に ある。
It's entirely your own responsibility. ???
are definitely understood, but certainly considered unnatural/incorrect.
So, in a word, you can split で ＋ ある for (strong) emphasis to insert the topic/subject.
(Just for completeness.) I guess you were asking about adding in more than a particle, because particles you can add in quite readily:
である ＋ も = でもある
である ＋ は = ではある
(Cf. でない ＋ は = ではない = じゃない & でありません ＋ は = ではありません = じゃありません)
Note that でもある is the only way to try to combine も and (the copula) だ:
This is a red pen. It's also a black pen.