Double clutching is fundamental to shifting standard transmission commercial trucks. Once you learn and understand how to do it you are well on your way. It can seem a little daunting at first but with a little practice you will get the hang of it.
Take time to get familiar with your gear pattern so you don't lose track of what gear you are in. Also get a feel for the "soft wall" to help hit the middle gears. Use your RPMs as a guide to help know when to shift up and when to shift down. Press the clutch pedal in the whole way when starting from a complete stop, then only a few inches while shifting on the move. Remember clutch neutral, clutch gear, for upshifting. Downshifting is similar with a small engine rev being done in neutral. Practice on an empty road, and it helps to practice while empty.
Hang in there, it will take some time to master.
