Are you following these instructions?

First of all, the 4 files ending with sha256sum are just checksum files to avoid corrupt downloads.

Probably the two files the instructions mentions and you are looking for, are:

• recovery image: lineage-18.1-20230613-microG-jfltexx-recovery.img
• LineageOS with microG image: lineage-18.1-20230614-microG-jfltexx.zip

I don’t know jfltexx and have only skimmed the instructions. Please read them carefully and always double check.

4 of these files are hash sums - they are just for checking that thw big files downloaded correctly

to answer your question we need to know - do you have any custom recovery installed on your phone? orange fox? twrp? if yes, then if i remember correctly you can just download a zip to your phones internal storage/sd card and flash this zip from the recovery. it should install boot image and all the needed files.

if you don’t have a custom recovery then i suggest looking into the description of the ROM (LineageOS) you are trying to install and looking which recoveries are compatible with it. it seems there is also a custom recovery image included in the folder you sent a link to, maybe it’s the only one that will work correctly with LineageOS. idk, so look into it and install the compatible recovery. usually if you don’t have any custom recovery installed that is done through the fastboot mode - when you can flash images over adb.

if anything i’ve said causes a “wtf what is this” then don’t worry, just read up a bit here. the article is a bit dated but the core concepts haven’t changed all that much.