@yuriythebest - The tabs you are reading are already in a position. If you’re reading tabs to Ode to Joy, you’re playing in 1st position. If you’re reading tabs to Whammer Jammer, you’re playing in 2nd position. If you’re reading the tabs to Scarborough Fair, you’re playing in 3rd position.
The last part of your question you seem to be asking about transposing a melody or lick from one position to another.
This is sometimes done, often transposing from 1st to 2nd position in order to “bluesify” a song.
For example, I first learned Amazing Grace in 1st position, starting on the 3 blow. Then I thought, “I wonder if I could play this in 2nd position?” So I figured it out starting on the -1.
But, unless you’re one of the lucky ones born with the gift of a superb ear (I wasn’t,) there’s quite a bit involved with this process.
I wrote about here: