There are multiple ways to demultiplex barcoded reads generated by Nanopore sequencing.
When starting a run in MinKNOW with live basecalling enabled, you can select the barcoding kits you have used and the software will separate your reads into barcoded folders containing the fast5 and fastq files.
In addition, MinKNOW offers a post-run demultiplexing function as described here.
Stand-alone Guppy may also be used from the command line to demultiplex after sequencing. Please refer to How do I use Guppy to demultiplex my barcoded reads? or the Guppy protocol for more details.