Deductions & credits

Thanks Mike. Can I deduct expenses from 2021 on 2022 tax return? Is this only referring to start up costs (computers, equipment, home improvement, furniture, etc.) that needs to be capitalized and depreciated over time? How about other expenses I incurred to get ready for airbnb in 2021 e.g. auto/travel, repair, cleaning, and supplies (bed linens, paper towels etc)?