Terraform is required. To install terraform see: Install Terraform
Cloud Provider CLI
Install the corresponding cloud provider CLI tool that you are using. Example:
Cloud Provider Credentials
If you need to set up the Cloud Provider credentials, here are the docs from the Getting Started Guides:
Terraspace currently only works on MacOSX and Linux. Depending on demand, Windows support may be added in time. For now, using something like Cloud9 IDE is probably your best option. All you need is a browser and you’ll have a fully working linux-based development environment in a few minutes.