Firstly, you may need create a new channel. Relate it with CakeHR or daily time off - you don't want your notifications being lost between #funnyanimals or #randomdevchat.
Next, head back into CakeHR > Settings > Integrations. Then, Enable Slack integration.
Select the appropriate channel and click "Authorise". Daily, at 8:00am according to your Global Timezone settings in CakeHR, you will receive your notifications directly in Slack, in the channel which you selected.
Here's an example of a daily notification: