I know where and how to find sugar cane but I don't know how to grow and farm it myself.
To grow sugarcane you must plant one piece (using the left trigger for Xbox, right click for PC) on a block of dirt or sand. The dirt or sand block must be directly adjacent to water. It will eventually begin to grow, and you can harvest it by breaking each "block" of sugarcane. You don't have to break the bottom "block" of sugarcane in order to harvest the others, so an effective method is to plant lots of sugarcane and then break the top two blocks, leaving the bottom one intact. This means you don't have to replant all the sugarcane every time.
To get sugar cane, you can find it on river banks and ocean shores. Similar to cactus, breaking any part will harvest that block and all above it. To plant sugar cane, put just one block of it in one block of dirt or sand next to still water by right clicking the dirt or sand block. When farming sugar cane, you can just let the sugar cane grow, and when it grows taller than 1 block high, break the second block. This will cause the second block, and all blocks above it to break, but the first block will still be planted and will grow again. Repeat this process to get more sugarcane.
sugarcane is found near small ponds if you finds some, punch it and then place it on a sand block (BTW a little secret most people don't know about sugarcane is it can grow underwater and in survival you can make a little breathing bubble with it i know it has nothing to do with the question but just a little tip)