If you're applying for a Finland tourist visa from Morocco, you can prepare a round-trip flight reservation without purchasing your final airline ticket first. The tourism checklist used for Finland applications in Morocco specifically asks for a return-flight reservation and says the ticket should not be bought before the visa is granted. That makes your immediate task refreshingly practical: decide when you want to visit Finland, map a believable route, and get a reservation that matches those plans.
Begin with the holiday you actually want
Finland is not one single type of trip. A long weekend in Helsinki looks different from a winter week that includes Rovaniemi, and both look different from a summer trip around the lakes.