And you won't find a way. PS/ACR is associated with opening RAW files.
To First work in LR you have to Open LR and click the Import button in the Library module. Then select the folder or memory card from a camera ( If a Memory card it most likely will Be Auto Selected by LR already) on your drive in the Left hand Source section. Pick which images to import, or leave them all checked to import all of them. Then click the import button.
I Strongly suggest you review some of the very good video tutorials available on the net on how LR works and the proper way, Best Practices, of working with LR. It will save you a LOT of headaches and make using LR more enjoyable. Otherwise you may find your self pulling out some hair.
http://www.jkost.com/lightroom.html
https://helpx.adobe.com/lightroom-classic/view-all-tutorials.html