Choose the target that is closest to the custom board. Eg. FRDM_KE02Z40M may be in your case.
Search the project for this define to see the locations where it is customised.
Decide whether to add your own define or whether you prefer to use this define and adjust customisations where needed.
At each location where it is customised (eg. size of RAM, size of Flash, clock settings, GPIO uses) change the defines to suit your board or your requirements.
Does uTasker support the custom board. For example I use for my processor MKE02Z16VLC4 If yes, how do I do this Thanks