how to make an aquarium, (100 gallon)?

I would like to know how to make an aquarium, if possible 100 gallons.
I have some koi, and i know that they live in ponds but we live in an
apartment so that isn't possible. I would like to make an aquarium
because buying one isn't good for my budget. I have more than 7 kois
in my aquarium. There are small, 3 inches being the smallest one and
about 7 inches the biggest one. For right now they could fit, but
later on, when they grow bigger its going to be a diffucult task. So
if anyone can help me out, i would really appreciate it.

I have research in the internet but they don't come with diagrams, i
would like someone to help me out with diagrams if possible. O yeah, i
will also like to know where i would have to buy the materials, like
the kind of glass, etc.

Thanks for your time to read this.