I had a couple of questions regards how to play the Bb chord.
Probably the most important thing is to drop the LH wrist which results in the thumb centering at the back of the neck. then use the 1st finger to barre the first two strings at the 1st Fret. make sure this sounds good. Drop the middle finger onto the 3rd string 2nd fret, again make sure all three sound good. Then place the 3rd finger on the 4th string 3rd fret. make sure it all sounds good. Keep working at this to make sure all strings sound good.
you may also like to try creating the chord the other way round. ring finger on 4th string 3rd fret, does it sound good? middle finger on 3rd string 2nd fret, 1st finger on strings 1&2.
Either way check the sound, adjust the wrist position, if your 1st knuckle inverts try to find a position that works where you can control the knuckle. I don’t know of a way round this its just keep trying.
There are many songs in the key of F , Bb is the IV so it will almost certainly appear in the song. So practice changing from other chords. As we know simplistically you can expect I, IV and the V to appear in songs. So use the key of F to give you the sequence – F, C Bb F or F, Bb, C, F . Don’t spend too long on this, for most people its better to do short session of 5 minutes a day.
Remember just try to get the Bb, if you don’t make it perfect its ok, I try to keep the ukulele police out of the session you will be safe.