Summarize the following:
Remove any nail polish by wetting a cotton ball, pad or cloth in nail polish remover and wiping it over your nail in the direction of the break to prevent more tearing. If the polish is very dark or has glitter, use an acetone remover. Next use either the finer-grit side of a regular emery board or the second-finest grit of a 4-way nail buffer and gently smooth the edge of the nail. Again, to avoid more damage, don’t saw back and forth when filing the edges. Both are thin glues that spread quickly, so you want to use them sparingly. Holding the break together with another finger, put 1 drop of either super glue or nail glue on top of the break and one beneath it. Use a toothpick or cuticle stick to spread it evenly along the length of the break, on both the top and bottom. Use the toothpick or cuticle stick to hold the nail in place for about 30-40 seconds.  You need to hold it long enough to help it stick but not so long that you’ll sever the bond that’s forming when you try to remove the cuticle stick or toothpick. These glues generally won’t last through numerous acetone nail polish removals, so reapplication will be necessary if you use acetone. Allow the glue to dry until it’s cool to the touch and not sticky or tacky. Because the glue won’t be smooth with the surface of your nail, take the coarser-grit side of the emery board or the second-coarsest side of the 4-way nail buffer and gently file the glue until it is nearly flush with the surface of your nail. Then use the finer-grit side of the emery board or the second-finest grit side of the 4-way buffer until there’s no ridge left.. Pay close attention to the edges, making sure they’re flush with your skin, too. This will help prevent the break from tearing, and it will make the break less noticeable. To remove any super glue around your nail or in other places, take a cotton ball or Q-tip with acetone nail polish remover and dab it directly onto the glue, which will dissolve after it has fully absorbed. Then wipe the area with a clean cloth. If parts are still stuck, don't peel or pick at them. Apply more remover and repeat. To remove nail glue, soften your finger, and other areas if needed, in warm water for 2-3 minutes. Gently remove any glue that is soft but still on your finger. For larger, stubborn clumps, gently file them down. Then use a cotton ball or Q-tip to apply acetone remover to the glue for a few minutes before wiping the area clean. Afterward, wash your hands well with soap and warm water.

Summary:
Prep your fingernail. Apply nail or super glue to the break. File the glue and nail. Clean your nail.