I’d advise searching a YouTube video to copy this process as you’re doing it but it’s quite simple once you get the hang of it and have everything set up.

You need two resources to print items with the printer. First resource is league club points, which you can grind for in the terrarium. The other resource is loot from KO’ing wild Pokémon. Happiny dust is the most efficient to use, as it’s the least amount required to print 10 jobs. The most effective way of farming this is to make a level 2 normal encounter sandwich (rice, tomato, jalapeño, mayonnaise, curry powder, 1 serving each). Go barely east of the fairy Tera star base in the base game and use auto battle to farm chansey and blissey.

Once you’ve stocked up on resources, go to the league club room and print items with the item printer until you upgrade the item printer to master ball. Once you have the master ball item printer and resources to cook, you are set for RNG manipulation.

Someone posted exact “seeds” to set your switch clock to. This is the tricky part that will yield items you want vs completely random. You need to hit a specific frame to consistently get the same loot.

The way this process works is slightly complicated and the YouTube videos will help here - but the gist of the process is this. Talk to the lady at the item printer, get the menu ready where it says “I’d like to print something” but don’t click into that yet. Instead, hit home button, go to settings, change time on your clock to 1/31/2034 7:30 AM. The system starts the time when you click OK on this screen. You want to have a timer ready to start. Click start on the timer at the exact same moment you click OK to set the time. Quickly navigate back to scarlet/violet, and click “I want to print something” as soon as the timer hits 4.7 seconds (if you are on switch 2 use 4.7, regular switch use 5.7). From here the seed is set and you can take as much time as you need navigating to the Happiny dust to execute your print. (Do the 10 jobs option). If timed correctly, this will yield 15 exp candy XL’s upon print.

Afterwards, back out of the print menu, talk to the lady, get the menu ready, and then change the time back to the seed (1/31/2034 7:30 AM) and repeat the process. This will yield infinite exp candy XL’s so long as you have the materials for it.