Yes, ypu need an rPi4 2-4GB. I snagged mine used from local, can't recall whether it was FB marketplace or craigslist or other but these are great resources for a camera or other addons.
First, it's vitally important that you treat this first part, the frame, as a foundationally important part. You want to ensure the frame is square all around, and diagonally (corner to corner). I recommend the Chaotic Labs corner square tool, and a careful measurement eye. Also have a small machinist square handy.
Link for example:
https://a.co/d/5Pd7Wg7
Learn to "feel" a flush meeting of two extrusions at the joint. Sensativity of the "finger feel" at 0.1mm or less is what you want.
Make sure you print all the ABS plastic parts from a carefully and completely "tuned" machine, as "engineering level" components If not, consider ordering the CNC aluminum gantry parts and belt tensioning components. You will appreciate this decision. It is worth the money.
As you build, start to form an understanding of how the assembly progressively builds upon the previous parts. It sets you up for understandjng how to tweak or tune the latter subsets of the machine.
Don't fret when you go to build the flying gantry, you can easily tune this later.
When you get to doimgnthe belt path of the gantry, pay attention. You will probably do this again within a year.
When you get to the electronics bay, take your time. Make cable paths efficient first, then organized. The neatness of the look will be hidden, but the wise cable paths you choose, being functional is better. Consider airflow, then cable lengths, then cable access. Skirts are pretty afterwards, remember that.
