Make sure you have pnpm installed on your system. You can install it by npm as well:
npm install -g pnpm
or on any POSIX systems by wget one-line official command:
wget -qO- https://get.pnpm.io/install.sh | sh -
for any specific cases or systems check the official page: https://pnpm.io/installation.
pnpm install
pnpm dev
Look at next.config.js and nextjs redirect docs.
Refer to contribution guide.