Cranks but will not start

Replacing battery literally four days ago. My papa came over and got the battery replaced and tightened the belts (both, serpentine and alternator belt)? I am not exactly sure what they are. He got those tightened and there’s a hose on top of the motor that has clamps on it kind of next to the battery, I am not sure what that hose is called and what it does, but he put just a little bit of gasoline in that hose and he got it to start. We drove it fine those four days, it started perfectly, everything. This evening to go to the store we tried to start it and it cranks, but does not turn over. Checked battery cables, they are fine. Belts are tight but we were going to go tomorrow to get new ones because he said they needed to be replaced but cannot unless we figure out why it will not start! It has gas in it, everything. What could this be?

I am sorry about how I described this. I am a woman and I know absolutely nothing about cars at all. Please help me!