To read tab, the numbers means the fret, if they are stacked on each other the notes are played at the same time like a chord. Tabs are written so that the low E string is on the bottom so it's like the fretboard of your guitar is facing in front of you upside down. That's kind of the base of it, there's more quotation markings that eventually should try to understand, possibly a legend key online with descriptions. Things like bends, palm mutes etc.
The Major Scale is like Do Rae Mi Fa Sol La Ti Do, so you find the first Do you want and climb up to the next in pitch. Could start any string, I saw earlier there's a tab of it starting on one string in lesson 7. I think it was the C Major scale to learn first cause there's no Sharps or Flats to start. Try to remember how it sounds so it's easy to find eventually. It's also playable in boxes/positions, on one string and I haven't tried it yet possibly string skipping and intervals.
When I'm jamming with a song usually I end up with a group of notes that sound good and I think that's a scale
maybe it's a lot at once