Get people involved. Theatre is a collaborative art and there is no limit to how many people can be involved. Use a group of friends who also love theatre or just need something to do. Put up postings about the potential group on community boards, libraries, churches or schools.
Find a space to meet, rehearse and perform. This does not have to be huge or elaborate. Try a community park, a church or temple, library community center or town hall. Many of these places are willing to donate space for positive things like theatre.
Advertise for help with resources. Many theatre artists such as costume designers, make-up artists, set designers, painter and lighting and sound designers are eager to get experience and are willing to share personal resources. Choose plays to perform that require minimal sets and modern clothing.
Name the group and establish a mission. Brainstorm names that will represent what the group is trying accomplish. If the group will be doing edgy pieces choose a name that represents that. If doing comedies or children's plays, choose a silly name.
Perform plays. Advertise and place posters to get an audience to come. Many schools and churches will be eager to watch plays that have a positive and moral message to present. Rely on word of mouth for success.