I'm a beginner and don't really understand how to play tied notes I think.
I'm learning(trying at least) a song with Guitar Pro.

1)It's like this:


5 and 7 are tied(so you should play 5 and just push down 7(so not play).Am I right?

And here in this song I'm playing 5 is wrote small and 7 normal.What does that mean?

2)And how do you play this:


and the two 5's are tied.

Hope someone can help me.
Its a slur - it means play the notes so they run together smoothly, rather than picking each individual note. Also called legato.

Hammer-ons, pull-offs and slides can all be used, but for slides you normally get a stright line joining the notes too, to indicate the slide between them.

However many notes the slur covers, they should all be played smoothly - so if you have 5-7-5 with a slur over all three notes, you'd pick the first 5, hammer-on the 7, and pull-off to the 5, and not pick again until the next note.

You also get tied notes which are the same tone - which is basically a way of showing notes that are held over more than one measure, or over more than one beat.

If the 5 is written small and the 7 normal size, it probably means the 5 is a grace note - which means you just play it quickly on the way to the 7. Its more of an embellishment to the 7 than a separate note in the piece.