M. Rhoten,
Someone must have told you about an alignment tool..right! No! You must not have installed a new clutch and pressure plate otherwise this issue would have come up.
Without a dummy input shaft or a wooden alignment tool it can still be done. Using the cool doohickey to level the tranny, run the snout into the bellhousing and put it through the throwout bearing and into the clutch splines.
Have the transmission in gear (low) so you can turn the output shaft which will turn the input shaft and make it easier to engage the clutch splines.
You have to have a helper in the cab to depress the clutch which allows you to wiggle it around and find the pilot bearing...hold your breath, wiggle and twist and it will go right in.
Stuart