This summary is not the rule. The rule text controls.
If your appeal gets dismissed because you missed a step in the process (something other than filing your notice of appeal on time), you may be able to get it back on track. You can ask the court to reinstate your appeal by filing a motion.
There are two main reasons the court will consider bringing your appeal back. The first is if you made an honest mistake, got caught by surprise, or had a good reason for missing the step, something the rule calls "excusable neglect." The second is if the other side in your case acted dishonestly, misled you, or did something improper that caused the problem.
Timing matters a lot here. You must file this motion before the court sends out what's called a remittitur. A remittitur is the official document that sends the case back to the lower court and closes out the appeal. Once that happens, it's too late to ask for reinstatement, so you need to act quickly if you think you have grounds to fix a missed step.