When people come to the meeting, you can pass a donation box to ask people to participate. It's important to share why you are asking money. What will the money be used for? At the early stage the money will be used for renting a meeting space, for supplies and materials for the art group, posters and stickers. If needed, funds collected could also be used to reimburse people who need financial support for their public transport. That could be particularly important if you create the first chapter in a given country or region and people need to come from afar. The cost of transportation shouldn't be a deterrent to be able to participate in meetings.