I have two parts. One part is the top half and the other part is the bottom half part.

1. Is this the correct way of doing this or shall I create one hole part? and then cut it in half using plastic tools, if so then how can I cut in half using plastic tools?

2. What shall I do with these two parts before I can add lip/groove?

PS! I know how to lip/groove. The Help is quite good on this point. But not the steps before.

Thank you very much!