First install terraform for your local machine https://www.terraform.io/downloads
Next configure your local credentials to manage the proxmox with your permissions by copying the init_example.sh to anything *init.sh and replacing the <terrafom_user> and <terraform_pass> values with your credentials to your proxmox instance. Make sure to use this convention so you don't accidentally commit your local creds to the repo.
Next run
myinit.sh
To test local syntax of code run:
terraform validate
To plan your change run:
terraform plan -out local.plan -var-file local.tfvars
Finally Execute the plan if everything looks good:
terraform apply local.plan