Go to the area where the chopper gunner is and make sure you have 1 friendly with a carepack, do this by swapping teams (in private match where you can put 1 kill per carepackage).

Crouch down by the first gap after the jeep that can blow up, crouch in the gap and then your friend (on your team) will throw the smoke can so that it lands as close to the gap as possible. You need to be crouching, moving forward but not moving much.

Try several times, it may not happen at the start.

Also remember to have a tactical insertion and don't run too far, you could fall under.

There's also many spots where you can stand and shoot under the map and not die. Ask these three gamertags for more help: Haroon98767 (me and founder), PFPxNUK3D3M (best mate and noob) and zR x Desiqnz (helper).