To save you some possible hassle in a couple ways,,
1. you won't get support on these forums regarding 16756 as Team Xebuild has not released the official files , the ones floating around the web are patched up versions of previous builds
2. I recommend only using the official XeBuild releases (latest being 16747) , that being said, use this method to update http://www.realmodscene.com/index.php?/topic/2205-xebuild-freeboot-nand-update-tutorial/ , It's can be done in 2-3 minutes or less and requires no file transfers or extra storage devices , by far the easiest way available
otherwise if you wish to use the old flashing method I have attached swizzy's tool below, but I will not provide any info on 16756 as I know the staff and devs here do not support it's use due to the current only viable use being online play.
Simple_360_NAND_Flasher_v1.3_BETA.rar
In a quick look I couldnt find the official thread on these forums for the program, but please drop swizzy a like or a thanks for his work if you use and appreciate his software http://www.realmodscene.com/index.php?/topic/3472-simple-360-nand-flasher-by-swizzy-v13-ou-v12/#entry26180