So I just had session 1 on my first ever online campaign. The story and people are good, but the DM added mechanics that confuses me to the point that I wasn't even listening to the campaign.

One of its mechanic is that ac doesn't exist, you have to roll a d20 and your number is higher than the attacker, you block the attack. If you miss the attack, something happens to you, preventing your action.

Another is the class skills not being level based, but you have to learn it. As well as when you level up it's 1hp and 1 stat boost.

All of those mechanic is confusing especially the health. I'm a Hill dwarf with a plus 3 con mod. But I have to increase my HP by 2 every level to 10, then every 2 level by 3, etc ..

Should I leave the campaign or talk with the DM that I don't like his mechanics. Since he barely knew about the dice roll con when leveling up for health

UPDATE: I left the campaign since the DM barely knew 5e rules except for what he saw from youtube videos. I'll find a better campaign someday.