To Complete GTA 5 Online Series A Funding Heist Bikers mission you need to reach the Lost camp near contractor's place by the Alamo Sea.
Your aim is to quietly get into the Lost camp, kill the guards and take the vans loaded with meds to the contractor.
In order to begin with things, you will need weapons, these can be acquired from contractor's trailer. After getting the trailer, go to the Dinghy past Sandy Shores to the Lost camp at Stab City.
As you need to use stealth, do not forget to silence your weapons while creeping into Lost camp. Coordinate well with your mates and plan a strategy.
When you are done with taking down all the Lost MC, your next task is to find the vans and take them to the contractor's warehouse. Your way back wont be easy, so there is no point in relaxing yet.
Driving to the highest speed will be an effective way out of the firing.