Shift + space toggles jumping automatically. The setting doesn't turn off when respawning so it does not have to be retoggled every time. This could be a setting as well I guess. Thanks!
If you never strafe jumped or played maps like these before, it's normal to not pass level 1. This game is about mechanical skill and getting better at it. Don't worry about falling off or restarting the level, it's more about the process and practicing strafe jumping / bhopping.