Commonly used for building prototypes and one-off designs these boards are general purpose and require soldering components/jumper wires/bridging connections. Generally way harder to build than a MiniPCB, for example.
Look at Amazon.com, Sparkfun.com, eBay, etc. for "protoboard". Some even have power buses and traces placed to help duplicate an existing circuit designed on breadboard. There are protoboards that take a Teensy3.2 and turn it into an (larger) Arduino UNO footprint. Then there are UNO "Shield" protoboards that plug into that. Lots of variations. and some of them are quite nice but they can start to cost a bit and the end result generally will fall short of a MiniPCB or MaxPCB.
OnStep can use different "pin maps" so be sure to pick one, Config.MiniPCB.h for example, and look at the comments and/or matching Pins.xxx.h so you know what to wire where!
The picture below was from when I was building my Takahashi EM10 controller on Protoboard. This controller was Teensy3.1 based (same pins a 3.2) with DRV8825 stepper drivers and used what is now the Config.Classic.h pin map. After I was done soldering I used a hacksaw to cut the PCB down to size. This was replaced with a much nicer and much easier to build MiniPCB. The MiniPCB added an ST4 port, WiFi instead of Bluetooth, SSS TMC2100 stepper drivers (1.5x faster slews and better tracking and quieter,) a PEC sensor input (that I use,) etc.
OnStep can use different "pin maps" and the following was designed for the Config.Classic.h wiring!
Not shown here but whatever you build use an appropriate DC rated fuse (current rating depends on stepper drivers/motors/etc.)