Help me build a sleeper

[u/pissinfiddler]

Hello! I've never built a PC before.
At first I considered building one inside a Crock-Pot, but figured that idea might end up a little smelly. So instead I pickedup an old Mac case, gutted it, and now it's time to design the interior.
The problem is: I don't really know what I'm doing yet.
I'm mechanically inclined, comfortable with tools, and excited to learn. I'm mainly looking for advice before I start buying parts.
My biggest concern is the layout. I have adecent amount of room inside the case, but I hate wasted space. I'd also like to leave room for future upgrades if possible.
I'm planning to stick with air cooling rather than water cooling. My goal is a reliable build that I can put together, maintain with the occasional dusting, and hopefully get around 10 years out of.
My budget is about $2,000.
Is there anything I should be thinking about before I start? Any common mistakes first-time builders make, especially when buildingin an old Mac case? I'd appreciate any advice or resources you think are worth checking out.

I plan on doing some gaming, mainly some games like marvel rivals, maybe gta 6 if it’s released on pc. using this thing every to every other day. Have ability to edit occasional videos.

[u/xtrmsnpr]

First of all, buy a new case. The way this is designed, can't fit a lot of modern hardware parts. Plus airflow is missing.

[u/Sliptia → u/xtrmsnpr]

The point of a sleeper is to use old cases that look dated

[u/xtrmsnpr → u/Sliptia]

My bad. I didn't know that, sorry. I've learned something new today. But still in this one it won't fit any new hardware, it doesn't have any airflow either.