so i'm kinda new at making figures and was asked to make a m&m themed birthday cake so i wanted to make the m&m characters for the top of the cake out of fondant or gumpaste and wanted to know what is the best way to put these guys together and make these guys stand on their own, they have thin legs and i don't think they will be able to hold their own weight,  anyone have any tips on making figures like this stand?  

there are many ways you can do it. consider that you may have to make the legs slightly thicker to allow them enough strength. i would mold the legs around a toothpick or a bamboo skewer and leave an end sticking out of each side so that you have some to stick into the body and some to stick into the cake. 

You can make the legs out of lollipop sticks covered in fondant, leaving enough exposed stick at the bottom to stick into the cake. Or put a toothpick, coated with gum glue or melted chocolate into the bottom of each leg. Then take pieces of drinking straw, slightly less than the height of your cake layer, and fill them with melted chocolate, then insert the toothpicks into the straws and pop in freezer to firm chocolate. Now you have something stable to stick into the cake. Does that make sense or did I sound totally confusing?