Step 1: Extract the .snippet file where ever you wish.
Step 2: Open Visual Studio and navigate to the top bar and find "Tools"
Step 3: Chose the option "Code Snippets Manager" and wait for it to open
Step 4: At the top where it says language, chose the option "CSharp"
Step 5: Go to the bottom where it says add, now the location you chose is up to you I setup a rust folder in "C:\Users\UserName\Documents\Visual Studio 2019\Code Snippets\Rust"
Step 6: You should now see your folder with nothing in it, click on the folder, navigate to the bottom of the Code Snippets Manager and chose import. Find where you extracted the file to and double click it. 
Step 7: On the right side you should see your folder, checkmark it and hit finish. 
Step 8: You should be all good to go now, try typing in a hook or one of the custom snippet.