Conduct a search and use the make and model of the product + “instruction manual”. In my experience, you can get the information faster online than by actually calling the manufacturer of your furniture.
All that said, convertible futons require very little assembly. In fact, they often arrive almost fully assembled except for the legs. Simply screw the legs into the base of the futon, and you can start sitting (or sleeping!).
Note: Quick assembly includes metal futon frame styles, DHP, Dorel, Klik Klak, etc..
(Tip: DHP products actually have a manual # that is listed on each product tag: look for “IM Number”, and you can reference this number when searching online or calling the company). You can view these instructions online or print them out for free. Therefore, you don’t have to pay any fee to have an instruction booklet mailed to you. =)
How to Put a Futon Together: The Package
Although they ship in efficient compact packages, they arrive in very few parts. Thus you don’t need to set aside a full afternoon to assemble your futon. Rather, you just need to allow about 20 minutes, maybe 30.
With convertible futons, you generally receive the main sofa. This includes the frame with attached mattress. In addition, you get the detachable legs. If you need any tools, like an allen wrench, they come in the package.
In the case of Dorel Futon assembly, the sofa comes with frame connectors. These slide into place and secure using the included hex screws. The legs also attach with hex screws.
Another benefit of having such fast and simple assembly is that the furniture can also be quickly disassembled to move if necessary. (Something you might not think about when initially purchasing, but which may come in later down the road). Just remember to keep any tools that you might need in a place that you can remember (like taped underneath the futon where you can’t see it – but can easily find it).