If the engine cranks robustly, the battery is ok. For cranks but won’t start the quickest way to a solution is to first determine whether the problem is no spark, or no fuel. It’s almost always one or the other.
Do the obvious stuff first of course. Make sure there’s enough gas in the tank. Nothing leaking under the vehicle. Hoses and connections appear to be the same as they always were, etc etc. Next, decide which you want to test for first. Usually spark is the easiest. Connect up a spare spark plug, figure out a way to ground it to an engine ground away from anything that might explode or catch fire, and watch for a blueish-white spark to appear at the working end while a helper cranks the engine. Report back on the results.