Can someone explain it to me? I heard that the transaction speed would be much more faster, but I don't know how it works
As you know that bitcoin transaction speed is very low at times and in a real world scenario this is not good. For example , if you are standing in a queue to buy some tickets for a match in bitcoins, and each translocation taking 5 to 10 mins, this will surely not help.
Here is where the Lightning Network will help to quickly process the bitcoin transaction.