Hi.
I suppose someone has to put up their hand and and suffer some ridicule and humiliation.
I Last played bass in a band front of people at a Queens Silver Jubilee party ...yes that long time ago. I was not very good at playing, nor was the rest of us in the band, just 12 bar cowboys out for a laugh. We did manage to get shut down by the police at a night club, for excessive noise ! a rendition of Argent ..Hold Your Head Up.
Last year I did buy another bass guitar just to make a bit of noise. This was a nice Ibanez, well gigged but it was set up nicely and felt o.k. to play. I picked up a cheap combo amp off of Gumtree. and when inclined I try to get my arthritic fingers working again and make some noise
So start off easy and learn 12 bar blues, there are plenty of free lessons on t'internet. In short probably choose the 8 notes in the key of C and play 1, 3, 5, 6, 7, 8, and go back down again as in 8, 7,6, 5, 3, 1, That will give you a nice melodic line. In time you will know that the same pattern of the notes exists in al the keys, but enough to get you through being a 12 bar cowboy. Listen to some decent Bass players and only play enough notes to fill in , do not get to complicated I hope that helps.
Steve.