To add all IPs in your MikroTik Simple queue, just open your MikroTik RouterOS terminal and run the following script:

:for x from=1 to=254 do={/queue simple add name="client-$x
" max-limit=3M/3M target="192.168.254.$x"}

Here in max-limit variable you can define max speed upload/download. For example I used 2M for upload and 4M for download. This simple loop script will easily add all of your IPs in your MikroTik Simple Queue. After that you can manually modify when you need for any specific IP.