Note: If you have a LinkedIn Recruiter account, connect it to Workable to use Recruiter job slots to promote your jobs on LinkedIn.
To link a premium LinkedIn post to Workable (without LinkedIn Recruiter), create a job in LinkedIn and purchase a pay per click budget.
After the post is created (or while creating it), edit it in LinkedIn and select the option to make changes to "How you’d like people to apply" menu. In that section, choose "Direct applicants to an external site to apply" and you'll be prompted to supply the URL of the external site which stands for your Workable job shortlink.
As soon as this setup is ready, candidates who apply to the job on Linkedin will be redirected to Workable job page to submit their application. The applications through this link will appear in Workable as normal with source tracking for LinkedIn.