Make sure you'r switch isn't patched before going through this and downloading the files, if you bought it new 2 months ago it's almost indefinite it's patched.
There are plenty of guides online in forums and on youtube, but here's some tips I think some of them leave out. Never boot to emu on Wi-Fi, and never pirate games.
Also if it is unpatched and you don't have an rcm jig my best bet would be the aluminum foil jig to put the switch into rcm mode