Sitting still with engine off most all transmissions will be hard to get into gear.
Is it still hard if the engine idles, you push the clutch in, and then promptly find a gear? The synchronizers should make it happen quickly with little effort and no grinding.

If it is still difficult check to see that the clutch disc is installed the correct way and it is not either rubbing on the crankshaft bolts or bottomed out on the splines on the input shaft.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-