You must have these functionalities on your work-at site as standard
CV database in the CMS (before posting online vacancies, search for candidates in your own CV database)
Open search field for vacancies and/or work terms
Link to multiposter in the CMS (you want to be able to open the vacancy directly from the CMS in a multiposter)
Show similar vacancies (also see vacancies BC and D in the vacancy details page)
Job alert (receive new vacancies by email)
Open application (leave your CV, data will be stored in the CV database)
Peer overview (which colleagues can you meet as a job seeker in the company)
Tell a friend module (share vacancy to relevant social media channels)
Contact form
Chat function (optional)
When you are at the controls of your own heavy construction industry email list career site, you should want to measure everything. Fully setting up Google Analytics is your first action point. Ultimately, you want to set up your conversion funnel so traceable that you can track your applications per search query and not just the number of visitors and applications.
Suppose you post vacancies on two job boards, number 1 and number 2. Job board number 1 gets you seventy applications, while job board number 2 gets you ten applications. In fact, that doesn't tell you anything. If you then know that job board number 1 results in four new employees and job board number 2 also results in four new employees, it might be wise to shift a large part of your marketing budget from 80 percent to job board 1 to 2 (40 percent instead of 5.7 percent).
This way you will learn better and better every month where you can spend your marketing euros.
Stop making assumptions
Everyone knows what a great career site looks like (the professionals think), but if you really want to know how your visitor navigates and whether or not they convert, you will have to A/B test. Use a (free) tool like Hotjar to track real web sessions of your visitors. You will learn a lot from that and you will see that small interventions in your career site can often result in big differences in conversion.