After sharpening both sides of the blade place it on the kits cone-shaped balancer. If one side dips below the other continue sharpening it until the blade rests level. Return the sharpened blades to the mower and reattach. If you have a torque wrench its a good idea to use it here. Often you need to tighten the blade mounting bolt/bolts to a specific tightness level. Typically measured in pound-feet your instruction manual should list these specs. For example my personal machine the Honda HRR216VKA between 36 to 43 lb-ft of torque is required.
Top 5 Lawn Mowers recommends the Sun Joe MJ401E to people with a small yard who dont want to spend a lot on a mower. The reviewer liked it overall for many of the same reason one might like any electric mower (no fossil fuels lightweight etc.) but he also noted that there were only three height positions with the lowest scraping the ground. And due to its 14-inch blade it takes longer to mow a lawn.
Fortunately the Snow Joe + Sun Joe Company backs the quality of the mower with a full two-year warranty. With a 14-inch blade this mower is meant for yards that are acre or smaller and the 16-inch deck makes it easy to get into tight spots.