I've already given you the formulas for vector motion in another post. So, either you don't understand vectors or you don't understand motion in more than one dimension.
Can you draw a crude diagram of roughly what is going to happen to the particle?
Imagine you were running with the initial velocity and someone was pushing you in the direction of the force. Or, that someone is pushing you in the ##\hat{i}## direction and someone else is pushing you in the ##\hat{j}## direction. You need to find some way to relate these things to the real world.
But, then you need the maths to turn a crude understanding into a precise solution. So, if you don't understand vectors, you'd better go back and revise them.