When using LinkedIn's job searching feature, where you see: f_TPR=r
this part of the url is the amount of time it searches in seconds.

r3600 is 1 hour
r7200 is 2 hours
etc.

E.g. here is a data analyst url I have bookmarked that I refresh every so often

https://www.linkedin.com/jobs/search/?f_TPR=r3600&geoId=101165590&keywords=data%20analyst&origin=JOB_SEARCH_PAGE_JOB_FILTER&refresh=true&sortBy=DD

This makes it pretty much guarantee you're an early applicant
which helps your chances of your CV/resume being reviewed