Take the belt off and align all three, be absolutely certain you are lining up the correct mark on the crank with the correct mark on the block. Make sure it is in neutral before doing this otherwise it is possible leaning against the front could rotate the engine. Then do the cam shaft and the pump. Check they are in line and fit the belt noting the correct direction of travel. Fit the tensioner and check the belt is at the correct tension. Rotate the engine with a socket and ratchet on the crank pulley one full turn until it is inline with the correct timing mark on the block. Check cam and pump are spot on. Check tension. Adjust if necessary. Once all correct, you should be good to go but just check it again to be sure. Once more and when you’re absolutely sure all is correct, reassemble any other parts then start.
All should be well. Just check for leaks and make absolutely sure your coolant system is full and has no air trapped at the top. Make sure hoses get warm.
Then let us know how you got on.