To specify which hours your Todoist tasks sync to, you can configure the mapping for Todoist tasks from the integration settings here:
Within the rules settings for the Todoist integration, Reclaim will set up two rules, one to sync tasks to your Personal Hours with a tag of reclaim_personal, and one to sync tasks to your Working Hours with a tag of Reclaim.
If you have custom hours, you can set up additional rules by selecting "Add rule" at the bottom left. Then, configure the rule for which projects it should apply to and sync to the custom hours you'd like:
The labels are synced from Todoist, so if you'd like a new label to use for tagging, you will need to create that in Todoist.