DO NOT use the lasercutter without having received instructions and official permission from an authorized person.
It's preferable to use the vinyl cutter to cut the stencils instead.
Sometimes we forget to order stencils with our boards and then need a quick solution to spread the paste on our boards. Here's a small howto on - well - howto.
You will need a thin durable material that is laser-safe. With authorization, you can consider PET sheets (brand name Mylar, but be cautious as many toxic plastics are also sold with that name). You can get it in A4 sheets that are 0.125mm thick. This will deposit 25% more solder paste then if you would order from most PCB fabs (like Aisler), the most common stencil standard is 100µm stainless steel. Resize your paste layer apertures to take this into account.
It's relatively easy to export an SVG that just works with visicut from the start. In the boardview you can find a "plot" menu point and in the drop down where it usually says gerber, you can also choose svg. Just make sure you have only the important paste layer activated.
You want to engrave instead of cut your shapes out of the mylar. A good starting point for engraving the stencil is 100 power and 80 speed in visicut. With a bit of fiddeling, you might be able to get a stencil that works for the RP2040, but for now you'll probably have to touch up some blobs.