What is a Mandala (曼陀罗)?


#1

Master Ri-Chang gives a description here:

站起来设曼陀罗,曼陀罗就是供养。为什么这个地方要设曼陀罗呀?这个曼陀罗就是我们……这个真正的曼陀罗叫作坛城,叫周界。换句话说,这个曼陀罗虽然是我们现在手上的形相,这个就是表示把我们所有、所有的一切都供养,所以这个现在西藏还保留着。
Lamrim Commentary Track 87A

And here is Wiki’s description:

That saying, I am still struggling to really understand the significance and how I can better visualise and use it in my practice.
Will hope to get a teacher to enlighten me on this.