Topjohnwu has made the installation of of his Magisk rooting tool much easier now as it’s all done from his Magisk app which you can download and install here.
After installation the App will indicate it’s version 22, which is the latest at time of writing, so all you have to do is click on the install icon at the top which will recommend the best method of installation and download its script to modify the boot file and then tell you to reboot.
Once this is done your phone is rooted so I would advise installing some tracker app to make sure none of your user-installed apps are doing something behind your back! App Manager is an excellent tool for blocking trackers, but it might stop some apps working if they need online analytical tools. Some browsers have this problem. Otherwise try AFWall+ to choose which apps have internet or LAN access. It will also block internet usage when roaming via your phone provider.