Adobe Premiere Pro - XAVC S video editing

I got problem when editing XAVC S videos. Here is my settings -

-intel i5,6400

-RAM 4 GB

-Intel HD Graphic 530

-Windows 10

-Sony A6500 (Sel35f18/64 GB Memory Card Class 10)

I transfer the videos (120 fps/XAVCS) to play memories. After editing slowmo, i save in XAVC S file and it saved as .mp4 (this confuse me??) which later i convert to MP4 and it saved as .MP4 instead of .mp4 .

Then i tried to import the videos to adobe Premiere Pro for further editing but it turns out to be lagging and the video have this green thing which result to failure.
I downloaded brorsoft because i read it can convert videos xavc s for adobe PP. But the brorsoft could not even detect any of the sony videos file to open.

So what should i do? where is problem? i wanted to do a slowmo video without losing the quality. Please help me.