Quote from amclavido
This will be my first Custom Map.
First thing to do, note in your post that this is a parkour map!
In the map, use /clear to empty your inventory and /gamemode 0 to make sure the player starts in survival mode. Right now we have a bunch of random blocks and are in creative mode. Are rules 1 & 3 the same? "Do not place any blocks" and "Do not put \ any blocks"?
I almost missed the first wool block -- sneaky. You'll need to power the rail by the starting area if you want it to work. In the first parkour area, I'm not sure the two block jumps are possible with the low ceiling, and I'm 100% sure the three block jump with the low ceiling in the next area isn't doable. In the last area with obsidian, I assume you meant for the player to make a diamond pick to break through, but you've only put one stick in the chest, so there's no way to build it. Maybe just put a diamond pick with high efficiency on it in the chest? Breaking through obsidian takes way too long to be enjoyable.
I'd suggest making the areas you parkour through a bit more attractive. Raise the ceiling for sure, as the current height makes your map impossible to complete, and maybe make it look like a castle interior or something else with a bit of visual appeal. I'm glad it's not just made out of iron blocks, but it is a bit plain. Beside that, the parkour seems solid and mixing minor puzzles in between parkour areas is a nice touch.