Hi Sophia
I haven't read the whole thread, so I don't know what else has been suggested already, and I'm not a beginner so feel free to ignore me! Nevertheless here's a few suggestions (which worked for me):
Listen to recordings of the blues. This will help you to know when to change from the C to the F chord etc. Once you've played the sequence for a while it will become completely instinctive anyway and you will change automatically.
Practise the ostinato left hand patterns on their own - a lot! The one in your first video is just about the easiest. Eventually you'll get to the point where your LH is on auto pilot and you don't have to think about it. This then frees up your RH to improvise or play variations on the licks and phrases you've learnt.
Learn the minor blues scale. In the key of C this is the following sequence of notes C Eb F F# G Bb C.
You can play this scale, variations of it, and virtually any combination of its notes over the entire 12 bar sequence. It will work over the F and G chords. Experiment with the notes in this scale and you'll be amazed how much you can do with it. Sliding from the Eb to the E whilst playing G and/or C above is one of the more common techniques in blues and boogie.
These next 2 are more advanced but something to aim for.
- Try recreating your first video in a different key. G is a great key for blues and boogie. My favourite in fact. Eb is also, perhaps surprisingly, very good because the blues scale is all black notes except for one note. But that is much more advanced and I wouldn't try that for a while.
- Try and learn a few other LH patterns. One that stuck with me and I still use to this day is the Jimmy Yancey pattern. I won't try and describe that here, but it's worth looking up. When I first started playing this one it used to throw my RH off all the time, but eventually after relentlessly practising it on its own for hours and hours it became easy. Perhaps something for the future.
Most of have fun with it!
Cheers
Simon
All round average Jazz, Blues & Rock player.
Currently working towards ABRSM grade 8.