Shopify collabs agreements

I am wanting to join collabs as an entry level affiliate program to test the waters for how this will go for our products. I have a great lawyer I can buy an affiliate agreement template from but can you customize your affiliate agreement through Shopify collabs? Do they already have one? I know how important it is to have your legal things right so I just want to check before going this route and any Shopify collabs advice would be appreciated!