If your baggage is shipped separately and you’re not travelling with much luggage then the train is the cheapest and easiest way to come to Groningen. There is a direct connection from Schiphol. If you are travelling with a lot of luggage, you might want to rent a van. A taxi from Schiphol to Groningen will cost you between €170 and €250 and can be booked online beforehand. You can also get your baggage posted from Schiphol to Groningen with PostNL, the national postal service.
One of the most used ways to buy second-hand furniture is Marktplaats. If you do not like online shopping, there are a couple second-hand shops in Groningen. One of the biggest ones is Mamamini, where you can find a lot of second-hand furniture. City Central also offers a Vintage Furniture tour.
You can read more about recycling in Groningen on the waste guide ("afvalwijzer"). If you want to recycle your old paper, there are often old paper bins nearby and old paper is collected once a month. You can recycle glass by putting it in the glass bins. Make sure to check if it is glass with a deposit ("statiegeld"). Many supermarkets have bins for batteries and light bulbs if you are looking to recycle those.