1994 Ford Ranger XLT 2.3?

I had to replace the timing belt because the old one broke. I locked the tensioner to the loose position during dismantling. I put the new belt on and can't get enough tension on it to make it seat into the camshaft pulley so every time I rotate the crankshaft pulley it slips time. Is there a way to force the tensioner back over? There's nothing to pry on to get it back over so I can lock it into the tension position.

You should always replace the tensioner when changing the belt.

Go to a garage/shop and rent a tensioner tool or have them reset the tensioner. When you put the timing belt over the camshaft pulley, clamp it with zip ties so it will not move. And put the pin or lock on the tensioner to the unarmed or disengaged position. And check first if you have the correct belt by measuring it side by side with the old one.