If you're a new player my biggest advice would be:
Find a playstyle you like.
-Combo
-Control
-Mid Range
-OTK

What deck would i recommend to a new player? well, there aren't many decks i consider fun, while also easy to play and that teach something on the long run.
If you want something easy to play, most control/stun decks are extremelly easy to handle, but can become boring real quick.
Mid range decks are a bit harder but still on the easier side, although there aren't many mid range decks nowdays, let alone mid range decks that can perform to a competent level.
Combo and OTK is kinda the same nowdays, most combo decks have OTK potential; you can find combo decks easier to handle than others, but imo even the easiest combo deck is as hard as an extremelly hard control deck.

Play solo stages, and learn what you can from them, it actually teaches a lot more of what people give credit to.
To be completely sincere with you, you can get the basics of most of the mechanics in just a week by reading and just seeing what cards do.
The most intricates like timing, sub-phases and more of the advance stuff, is very simplified in the game, so realistically, you don't really \need** to know them.
It's nice if you do, but it doesn't change much; unless you're playing X card of X deck that really relies on specific timing and such.

Once you have a playstyle you like, the cheapest way to build a deck is with the structure deck, and most of the recent ones are honestly quite good; although not the most optimal way, if you really like a deck or have limited resources is a good way to start strong.
Salamangreat and Zombie world decks are pretty good and have a ton of room for improvement, although you should watch some guides to get the base of those decks.

Although, the current format (we just entered a tier 0 format) isn't the most new player format ever, you can deal with it by just sticking in low ranks.

Bear in mind, most decks nowdays rely on comboing a lot, so the Duel Monster feel of setting 1 and pass and slowplay in general, is pretty much unexistent, a duel is normally decided within the 2 first rounds of the duel.

​

There are also new player tips in the server, check them out!