OK- first off-- the great majority of lead guitarists use a pick- they do not fingerpick. There are some, however, who do (Jeff Beck and Mark Knopfler are a couple who readily come to mind). Fingerpicking is used predominantly as an acoustic technique.
As far as reading TABS go, one of the limitations of that format is that there is no good way to show timing (i.e. you don't have quarter notes, 8th notes, etc) so if you don't already know how the song is supposed to sound, then you're out of luck. TABS give you the notes to play, and they rely on you to already know how the song goes.
Since you're already familiar with Ultimate-Guitar.com, check out the lessons page on there for beginners:
For Beginners | Lessons @ Ultimate-Guitar.Com There are a few lessons for beginner lead guitar. Although you have been playing acoustic for a while, you are now looking at a different beast, so to speak, with the electric and playing lead. So, back to the basics to make sure you fill in the gaps for your current knowledge. You also may want to check out the lessons on how to read TAB on that site as well.
Bottom line is that when it comes to lead guitar, if you're planning on learning to blister the snot out of the strings, you're going to need to learn how to use a pick rather than just your fingers.
And how do you play that song? One note/chord at a time, just like every other song
Like I said, the notes are there, you just need to play them in the right rhythm.