See the official install instructions at http://docs.arednmesh.org

Download the Mikrotik .bin and the .elf file from downloads.arednmesh.org location:

•  elf  :  this is the image to boot the mikrotik device with.  It only uses RAM on the device (which is lost with a power cycle and still boots with Mikrotik OS)
• .bin :  once the device is booted with the .elf image and running,  copy this up to /tmp and type a command that will update the flash with AREDN, so it then boots AREDN on a power cycle.

Linux procedure:

1. Create a directory on your laptop /tftp and copy down the mikrotik .elf image
2. Rename this image to rb.elf
3. Set the laptop to static IP address 192.168.1.10
4. Become root to execute the dnsmasq command in step 5 
5. Figure out what your network card interface name  is with an 'ifconfig'  ('ipconfig' on windows.)    this is the interface you set to 192.168.1.10.  replace the name of the interface in the following command from "eno1" to what ever yours is.   replace your typical login name in the command from 'joe' to whatever you login with:
    

   Command Line Example:

   dnsmasq -i eno1 --dhcp-range=192.168.1.100,192.168.1.200 --dhcp-boot=rb.elf --enable-tftp --tftp-root=/tftp/ -d -u joe -p0 -K --log-dhcp --bootp-dynamic
6. Connect the Mikrotik device with your laptop ideally through a dumb switch.   Although, you may be able to connect them direct.  For the hAP-lite, connect the cat5 into the internet port.
7. Push the reset button on the Mikrotik, then power it on.  Hold the button until you see output log information from the laptop window where you ran the dnsmasq command, around 20 seconds.  Let up the button as they start communicating.   When you see the "sent" message, this is success and the Mikrotik has downloaded the image and will reboot. 
8. After the image is sent, as shown in the dnsmasq log, you need to <ctrl>C or kill dnsmasq.  
9. The node has booted AREDN,  it looks like a firstboot, but no settings can be saved.   Don't bother with the browser and trying to configure it.  It is in a mode where you have to load the image to the devices' flash now. 
10. Change your laptop back to DHCP mode to obtain an address from the mesh node, after it boots.  On the hAP-lite move the cat5 to an AREDN LAN port.  From left to right the ports are WAN, LAN, LAN, LAN, DTDLINK.    You should be able to "ping" the device at 192.168.1.1.  If this doesn't work, then something isn't right. Don't proceed until you can ping it.
11. Navigate to the Administration page:  http://192.168.1.1:8080/cgi-bin/admin (user = 'root' password = 'hsmm'. ), "choose file" the .bin firmware file, uncheck "keep settings", and click "upload".  The device will write the image into flash and reboot.   Wait about 4 minutes and proceed with normal instructions to configure device at firstboot​