Most of the parts I had left over from previous projects. The only thing I had to buy were the CPC1333G chips and I got those from DigiKey:
https://www.digikey.com/product-deta...388-ND/3077506
Mouser also has them. I tend to get most of my chips from those two places. The circuit board and terminals can be found in sets at a lot of different places including Amazon and eBay. I just bought a set off of Amazon for making my spindle encoder board:
https://www.amazon.com/gp/product/B07PD1HFHQ
I haven't actually used it yet so this is not an endorsement of that particular item. You can solder the CPC1333G chips directly to the board but I prefer to use IC sockets so they are easier to replace if necessary. A single 24 pin DIP socket is sufficient for this board. I had a couple of 14 pin sockets laying around so I used those with a gap between each pair of chips. You can find the sockets at DigiKey, Mouser, Amazon, or eBay. Depending upon where you live there may still be an actual electronics store locally that may have them.
For the resistors, 1/2 watt and pretty much any tolerance will work. Might as well get them from where you are getting the chips. Note that if you aren't using 24VDC for the 7i77 Field I/O then the resistor values may need to be changed.
As for reading the schematic, just follow the lines. Any big dots are junctions. Squiggly lines are resistors. The CPC1333G chip pins are labelled on one of the drawings. Pay attention to orientation. For each axis, I have the chips flipped 180 degrees since one chip is output from the 7i77 and the other chip is output from the AMC drive.
A disclaimer... I am not an electronics pro, just a hobbyist. I have only been using the board for about a month and it functions as I expected. Before you go through the effort of making this, do make sure your drives are functioning properly if you haven't done so already. Go through the drive setup section in the manual I referenced earlier as it walks you through this.