Advancing Code Review and Unit Testing Practice

Question

As a team lead managing a group of developers with no experience ( and see no need) in code review and unit testing, how can you advance code review and unit testing practice?

How are you going to create a way so that code review and unit testing to naturally fit into the developer's flow?

One of the resistance of these two areas is that "we are always tight on dateline, so no time for code review and unit testing".

Another resistance for code review is that we currently don't know how to do it. Should we review the code upon every check-in, or review the code at a specified date?