Please inform me!

I Don't know how Syncros and XYZs work. Can someone explain how they work?

have you read the rulebook?
you can find it here.
http://www.yugioh-card.com/en/rulebook/

Moved.

Basicly,

Synchro monsters are summoned from your extra deck by sending 1 face-up "tuner" monster and 1 (or more) non-tuner monster(s) THAT HAS A CERTAIN LEVEL to the graveyard, depending on what is written on the card.
The total amount of levels of the monsters that you have sent to the grave has to be equal to the level of the synchro monster you are trying to summon.

Some synchro monsters need only 1 non-tuner. Some synchro monsters can be summoned using 1 or more non-tuners and some synchro monsters are summoned using 2 or more non-tuners.
However, in all cases you need a "tuner" monster.


There are some special occasions on synchro summoning a monster (e.g. using 2 tuners instead of one, using a "tuner" that is a warrior-type monster, using warrior-type non-tuners, et cetera), so read the card texts on your synchro monsters very carefully.

As I have mentioned, synchro monsters need to be summoned using monsters that have LEVELS.
All monsters have a certain level, except XYZ monsters.

XYZ monsters have a RANK and do not have a LEVEL. Meaning that XYZ monsters cannot be used for the summoning of a synchro monster.

So how are XYZ monsters summoned?
It is called "overlaying".
Say an XYZ monster is rank 4, then it would require a certain amount of LEVEL 4 monsters (mostly 2) to be placed on top of eachother with the XYZ monster on top of them.
If an XYZ monster is rank 3, then it would require a certain amount of LEVEL 3 monsters to be placed on top of eachother with the XYZ monster on top of them.
Et cetera.

Like this ----V

Again, the conditions to summon an XYZ monster mey vary (e.g. overlaying more than 2 monsters, putting the XYZ monster on top of another XYZ monster (reffering to Number C39: Utopia Ray), et cetera) depending on the XYZ monster, so also read the texts of your XYZ monsters very carefully!



On a sidenote:
The fact that XYZ monsters have a RANK and not a LEVEL means that they also cannot be used for the ritual summon of a ritual monster. Or for that matter any action that requires a monster that has a certain LEVEL (e.g. the summoning of Sorcerer of Dark Magic)