Hello, long term Flyertalk lurker first time poster!

I'm traveling on the Eurostar to Amsterdam tomorrow morning in Standard, I have a Amex Platinum charge card so I believe I can access the lounge at St Pancras. My question, that I can't seem to find on the site is where do you go as a Standard ticket holder? The site mentions going through the check in gates then to the lounge but I'd assume most people would be on the top ticket or have Eurostar status so is it near premium check in?

My second question is how long before the train leaves should you leave the lounge. I've seen references to a 30 minute cut off for Standard and 10 minutes for Business Premier and status holders, does this apply to initial check in or leaving the lounge / boarding?

Thanks for any replies, simple questions but I'd like to know the process / step by step guide as I'm travelling with father in the morning and we don't have a massive connection time.