It can take years to master a martial art form, but learning a few simple moves can keep people safe on the streets, a self-defense instructor told an especially vulnerable group Saturday. “The techniques you learn have to be simple, quick and effective,” Nick Chamberlain told about 100 members of the city’s LGBTQ community Saturday at Juanita Craft Recreation Center in South Dallas. The Dallas Police Department organized the free training session after a series of assaults rocked the community this year. Chamberlain, a 10th-degree black belt who runs Chamberlain Studios of Self Defense in Dallas, said he felt compelled to lead Saturday’s training because the LGBTQ community is particularly vulnerable to hate crimes. “This group, the LGBTQ community, gets picked on more,” said Chamberlain, who for more than 40 years has traveled the country to teach various groups to defend themselves. “And when they get picked on, it’s more violent.”