if i have a sheet music in front of me or someone ask me to play a jazzy solo or walk the bass etc, i just fall apart.
Not sure if you just generally want to know theory, or if you specifically want to be able at those three things... which are rather different by the way!
My general recommendation is to work towards your goal i.e. what you want to be able to play (in the fairly near future, not your ultimate life goal) rather than planning a big study first and figure out what to do of it later.
However, if something inside you inspires you to study something just because, by all means do it! Studying out of inspiration will make you absorb knowledge and build skills faster than studying something out of duty.
1. How i practice scales and apply it on real life situations
Major, minor and pentatonics already go a long way.
Do you want to be able to play a scale more or less across the whole fretboard? Find songs or recordings (or create them yourself) in a fixed given key, keep a chart of the scale on the fretboard in front of you, and improvise on top of the recording. If your goal is to memorize the notes on the fretboard, start on a box and gradually move out and towards neighbouring notes to expand your range. Try to identify shapes that help you visualize and therefore remember better. Gradually look less and less often at the written chart.
2. How i improve my improvisation and my solos
Once finding the notes on the fretboard is not your main concern anymore, you can dedicate your attention to the actual content.
Some ways to improve your melodic content:
- sing a phrase first, then play it (usually we are more inspired by singing because we're not impaired by the worry of how to physically generate the notes! On an instrument we often worry and let our fingers dictate the notes instead of our mind)
- try the same one phrase many times, with variations until you find your favourite
- when you find a phrase you like, write it down so you don't forget it; you can keep the list of your phrases in front of you when improvise again
- steal phrases (not whole solos!) from any existing songs
3. How you manage to structure your practice routine if you have +3 hours of time for practice the bass
There's a million good ways to do that.
Maybe in your case, assuming you currently want to dedicate all of it to improvisation, the structure of those 3 hours is not that important. Also, a "routine" is mostly needed to combat lack of motivation or procrastination tendency, it is not necessarily the most effective way to learn. You can spend your 3 hours differently each day, improvising on new songs or learning a new scale from time to time.
4. Books? if yes what books for reading in bass clef or anything else
This question I don't understand... for reading in bass clef you can use ANY page in standard notation. Maybe there are books specifically with reading exercises designed to increase reading difficulty, but just grab random songs transcriptions in standard notation and set your own reading speed.
