$ npm install -g svelte-language-server # Make sure the global bins are in the $PATH, though you can change the lsp path
$ cd ~/.local/share/lapce-stable/plugins/ # Enter plugins directory
$ git clone https://github.com/coffee-is-power/lapce-svelte # Clone repo
$ cd lapce-svelte # Enter svelte plugin folder
$ cargo i # Compile plugin
And then (re)open lapce, and you're done!