It takes several steps to make string. First, you need to build the "Bash Research Station" from the "Research" group of equipment. The "Bash Research Station" is made with two logs and four planks. Once it has been built, you need to use a shovel to dig up about 10 weeds. Add the dug weeds to the "Bash Research Station" until the research has finished and the blueprint for the "String Maker" appears in the "Misc" group of equipment. The "String Maker" is made with six planks, four poles, one gear, and one stone. Once the "String Maker" has been built, you then add five dug weeds to it to make string.