How to complete all Chess.com achievements?

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Avatar of nguyencpuo

Hi everyone,
I’m trying to collect every single achievement on Chess.com (both easy and hard ones), but there are a few I’m not sure how to get.
For example:

What exactly does Public Game mean, and where do I play it?

For First! (first comment), are there any special conditions?

If I play 4 Player Chess in the Variants section, does it count toward the achievement

If anyone here has managed to get all the achievements, please share your tips and tricks.
Thanks in advance!