AnandaHya, you've got the whole thing, everyone of those scriptures has all your answers. I know some are a little harder to understand then others. There's no way to go over everyone on here. Have any suggestions? They all connect.
Here's a simple way to start. As you have above, start with Ex. 20:8-11. Sat. is true sabbath, but for the sake of arguement, if you keep sun. then keep it the way these verses say. Don't make it more complicated than it is.
1) No work or labor, (i.e. going to work, cleaning house, yard work, anything that even the world looks as work)
2) No buying, selling, etc. no stores, restaraunts, gas stations, garage sales, etc.
3) Do not cause anyone else to work.
Prepare everything the day before or couple days before. Groceries, cleaning, gas, etc. Then on Sabbath this is where Isaiah 58:13-14 comes into play. Completely denying self, and spending this day in Him, Bible study, prayer, worship, going to church, etc. Allowing YHVH to come and minister to you, this He can't do when we are running around like chickens with our heads cut off. Ever since I have kept Sabbath the way Scripture says, I have never felt so close to YHVH. I study and read and pray daily, but the whole Sabbath is set aside for Him and that's when I can get really get fed. I'm free from the worries and stresses of everything else, work, house, etc. YHVH has my undivided attention for that whole day and it's AMAZING.
Start with this if your willing, then YHVH will start giving you revelation as to how the rest works. There are some things that are out of our control, but it's the willingness to try and do what we have control of. YHVH will make things happen in ways you thought not possible when you show Him that your determined to honor His Sabbath. Shalom