Can I get someone else to do the construction salary negotiation or to negotiate my compensation package?

Yes. You may not be comfortable negotiating your own package. You can work through a placement service, or you can work with a construction career coach. Either way, you will have to do your own research to determine what you will and won't allow in your package negotiation. Your coach or placement service may help you with construction salary negotiations, but in the end you will be responsible for accepting or rejecting the deal. Know the job, the value, and the details of what is and is not reasonable for a compensation package for that job.