A multi-colour board is exported as one object per piece, one part per colour, each part already assigned to a filament slot. Import it the right way and your slicer shows every colour on the right filament, with no painting.

Filament slots

Pegboard Maker numbers the colours of an export once, for all its files:

F1 is always the base colour — the body of the board.
The other colours follow, largest volume first.

The README.txt inside the ZIP has a filament table: slot, colour name, hex code, approximate grams of PLA and what the colour is used for. Part names repeat the slot, so you can check the mapping in your slicer’s object list: Body [F1 Ivory] in the Bambu Studio / OrcaSlicer file, [T1 Ivory] in the PrusaSlicer file.

Slicers pick their own display colours for new slots — set each slot’s colour and material to match the README before printing.

Which file to download

Your slicer	Export format	File name ends with
Bambu Studio, OrcaSlicer	3MF · Bambu Studio / OrcaSlicer	`-bambu-orca.3mf`
PrusaSlicer	3MF · PrusaSlicer	`-prusaslicer.3mf`
Any other slicer, or single colour	STL (one file per part)	`.stl`

The Bambu Studio / OrcaSlicer 3MF is a standard 3MF, so it also opens in other 3MF-aware tools and viewers, with colours shown.

Bambu Studio and OrcaSlicer

Select your printer and process profile as usual.
Import the file: File → Import (Ctrl + I). Select the 3MF — or all the plate files at once. Importing creates as many filament slots as the design uses, automatically.
Dismiss the config message. Bambu Studio may say “The 3mf file has invalid config, load geometry data only.” That is expected for any file not saved by Bambu Studio itself: it keeps the geometry, the part names and the filament assignments, and uses your own printer settings.
Match the slots. In the filament list, set each slot’s material and colour to the README table. With an AMS, map each slot to the tray holding that filament in the print dialog.
Slice and check. In the preview, the first layers should show your inlay colours; everything above them is the base colour.

Saving purge: colour changes only happen in the first few layers, so waste is already low. You can cut it further by enabling flush into objects’ infill — the infill is hidden inside the board.

PrusaSlicer

Choose a multi-material printer profile first — for example an MMU or a multi-tool printer — with at least as many extruders as the design has colours.
Import: File → Import → Import STL/3MF/STEP/OBJ/AMF (Ctrl + I) and select the -prusaslicer.3mf file.
Check the parts. Each piece arrives as one object whose parts are already assigned to extruders T1, T2…
Set each extruder’s filament to the README colours, then slice.

Use PrusaSlicer 2.9. Early 3.0 test versions import third-party 3MF files as shapes only; if colours don’t come through there, use the STL files.

STL files

STL has no colours, so the export writes one STL per part per piece, named like garage-wall-a1-inlay-f2-red.stl: the f2 is the filament slot.

Load all files of one piece together (select them all in the open dialog).
When the slicer asks whether to treat them as one object with multiple parts, answer Yes. The parts share one coordinate frame and stay perfectly aligned.
Assign each part’s filament from the f number in its name.
Repeat per piece. A -x3 suffix means print three copies of that piece.

Printing on a single-extruder printer

Everything prints fine in one colour: assign every part to the same filament. The inlays stay flush with the surface and simply match the board. For a two-tone look without a multi-material system, give frames and panels (shaped panels) or caps and strips a different colour — they are separate pieces, so each is a single-colour print.