Large Cardboard sheets and paint and a thick paint brush (Kirkstall LS5)

Hi everyone I am looking for large cardboard sheets and green paint and brown paint I am wanting to make my own army base for my gi joe figures I suffer from autism and anxiety and lately my anxiety been rally bad lately so I am looking for things to make and help me with my anxiety if anyone can help me I be very grateful all I can offer is a cup of tea or coffee as a thank you I can't collect due to problems with walking and back problems