Theses, Books, Title pages ⇒ The Legrand Orange Book - Styling Chapters as Parts

[lmnd]

Hello everyone,

I'm struggling with a complex layout configuration.
I love this template and specially the Part header as full page with a mini table of contents for the part. But, unfortunately, I don't use parts in my document.
There is anyway to use the parts layout on the chapters layout?

I tried to recreate the structure configurations but without any success.
I tried to use parts as chapters, but the numbering doesn't work.

Thanks in advance