Not bad
You can build on this alot though and make it really cool with a bit of work. You mainly need some more stylistic elements, maybe add different types of weapons being used. A good idea might be to add a mortar to the squads and have a soldier or two get killed that way on the field. Some grenades, missile launchers, etc. might also be a pretty good idea. You might also think about adding some more angles to the scene, maybe when the soldiers hop out of the tenches, have an angle where it looks like the camera is actually in the trench and it shows the soldiers climb out. Not too bad though overall, just need to put more of your creativity to it