I need some help in this finger tapping part on this guitar tablature, help please?

The song is the Trooper by Iron Maiden there is a part that there is 5 - 4 - 2 in the 4th string, but there is a curved line on top of the 5 to the 2 (it skips the 4). And there is also an inclined line (one of those lines that represent sliding) from the 4 to the 2. I believe this is called finger tapping slide or something. I don't understand how to do it, help please? (BE VERY SPECIFIC AND HAVE MANY DETAILS)