If you are fanatical or bored, you can, like I did, polish the back using as fine an abrasive as you like until it looks like this:
The next step is to sharpen the bevel. Chisel and plane blades are typically sharpened between 20 and 30 degrees, lower angles being “sharper” but not as durable. I sharpen my paring chisels at 20 degrees and my mortising chisels at 30 degrees. Using a honing guide, it should be just a matter of setting the blade in the guide and going back and forth over the stones until you see a consistent band of gray along the edge of the chisel, just like when you lapped the back of the blade.
If you can’t tell which part of the bevel you are sharpening, put some permanent marker on the bevel and go back and forth on the stone a few times to see where the marker has been removed. When you establish an even band of colour along the edge of the tool, you can go to a finer level of abrasive and work your way up to your finest stone.
If you want to emply a micro-(secondary) bevel, do so on the finest stone and it will only take a few strokes to get that micro bevel. When establishing the primary bevel, I spend a fair bit of time on the stones and use a honing guide. When I touch up the edge by honing the micro bevel, I find it quicker and easier to do this freehand.
Now your blade has a nice flat back and a brilliantly-honed bevel. But you are not done yet. With all the metal you’ve removed from the bevel, you’ve created a slight wire edge on the back. Turn the tool over and lap the back with a few strokes on your finest stone to remove the wire burr. I find it easiest to take the tool out of the honing guide first.
There are many ways to test for sharp. My favourite is seeing if the blade can cleany slice the end grain of a soft wood such as pine. The end grain of softer woods is the ultimate test because only a really sharp blade can cut it cleanly.