WINSTON — After serving four years in the Marines, Aaron Snell struggled to apply what he learned in the military to civilian work. This used to make the 46-year-old Roseburg resident resentful. His feelings changed after finding guidance at the Silver Tree Veterans Services in Winston. Snell got help there applying for grants through the GI Bill. Now, he’s eager to go back to school to acquire skills for a job in construction. “It’s taken me quite a few years to figure out the direction where I want to go,” he said. “I’m real thankful I got these grants and …