I want to do positional accuracy analysis by using QGIS 3.16, thus I need to do buffer zone around the vector layer (I am using buffer in geoprocessing tools). However, the result of buffer always thousands of buffer zone. I have followed the guide to do buffer line from a video on youtube, in the video, it said I have to click on 'selected features only'. But, the problem is I cannot click it.
here's my file that I am working on. https://drive.google.com/file/d/1YKAkvkTtudvw_jVYKL9cKICAW_2_akKm/view?usp=sharing


