Install using Plug
Plug 'valk-lang/valk-vim'
Install vim-lsp using Plug
Plug 'prabirshrestha/vim-lsp'
Then add this to your .vimrc
if executable('valk')
au User lsp_setup call lsp#register_server({
\ 'name': 'valk-lsp',
\ 'cmd': {server_info->['valk', 'lsp', 'run']},
\ 'whitelist': ['valk'],
\ })
endif