my car won't start and i have a new battery ineed some help

Does it crank ? I'm assuming it cranks slow and doesn't start.

Dirty Battery terminals are a common problem, so are bad grounds.

If no cranking at all, could be starter / solenoid One easy test
is to turn on lights and crank over, if lights do not dim, starter /
ignition switch bad. If lights go out, bad starter, bad connection

If engine cranks quickly, crank sensor, ignition module or such bad