As soon as I try to run the mana-toolkit in kali using the command: bash /usr/share/mana-toolkit/run-mana/start-nat-simple.sh
Error shows up as shown in the picture mentioned
please help me with the possible solutions for this
The error messages from the script tell you everything you need to know.
The script cannot find wlan0. So you probably need to specify a different network interface. One that is configured and active. What is the actual content of the script you are trying to run?
I'm not a Kali user, but perhaps look up the usage information for the script. Maybe you can pass it a parameter that specifies the correct network device to use.
So perhaps try: bash /usr/share/mana-toolkit/run-mana/start-nat-simple.sh --help
Otherwise you'll probably have to edit the script.
The link provided has step by step instructions on how to install and setup the Mana-Toolkit. I have not used it but looks pretty straight forward. Why are you wanting to use Mana-Toolkit? There are some other tools that do the same thing with out the manual configuration. https://tools.kali.org/tools-listing