If your goal is to be able to improvise solos then you should learn some scales first. Scales are the building blocks that solos are made of.
Here are some suggestions for you:
- Start by learning an easy scale, like A or E minor pentatonic shape. You can find them in-app under Workouts --> Scales.
- Play the notes of the scale in different order, up and down, repeating some notes and jumping over others. Concentrate on melodies instead of speed.
- Play over some backing tracks, e.g. in YouTube search for A minor pentatonic backing track, and practice soloing over that. Again, forget speed, concentrate on playing in good time with the band (listen to the drummer!).
- Learn some licks from your favorite guitarists and try using them in your solos.
- Some other useful scales to learn: blues, major, minor, dorian, mixolydian