I rent an old farm house that has a jensen wood burning furnace and would like to try using it this winter but I don't know how to use it. Any help would be appreciated.

Just look unger Google for general wood stove operating tips.

First check the Chimney for any defects have it swept clear of any old creosote or insect or birds nests etc clear it all away so everything is clean never ever start a firewood furnace without first cleaning everything thoroughly first then check to see if everything is working properly the flue opens and closes properly the handle needs to fit onto the shakers and move those shakers (Grates) at the bottom of the stove properly and that all of the inner bricks are still well maintained once you are sure everything is connected and working properly the blowers are working etc you are pretty much ready to go. Newspapers or old magazines works best tree bark helps to just fill that first into the fire chamber then add a layer of small branches and light once they are burning add the bigger logs first being sure those logs will fit into the box though they can light fast if they are dry and you don't want to have to pull out a burning log that is already lit. I always shut the door and opened the vent on the bottom of the door peeking inside to make sure it was still burning well before walking away. I might have forgot to mention open the flue when starting the fire or the house will smoke badly. Once the fire is burning push the flue back until it is nearly completely closed but you only do that when the door is closed. We've been using our Jenson since the 80's it's saved us thousands of dollars over the years in fuel expenses love it and currently looking for a new one because our old one is no longer safe.