Here you start with 40 life and play best out of 1.

Your deck must have a LEGENDARY CREATURE as your commander, and no card in your deck may have a manasymbol not found on that commander. (there are 5 Planeswalkers that are allowed to replace your Commander)

Your deck must be exatly 100 card including your commaner, and all cards are restricted to one copy exept the 11 Basiclands, Shadowborn Apostle and Relentless Rats.

Finally, there is a specific list (of cards you cannot play in your deck)

https://magic.wizards.com/en/banned-restricted-list

No sideboards are used.