Need help with verbs

[nickmen2]

Hello everyone! Happy new year.
I have began to learn Japanese 2 weeks ago. I have chosen to start Rosetta Stone just to get familiar with the language. I have a question about the verbs "Desu" and "Arimasu". I understand that the verb "Desu" means "to be", covering "i/is/are". I am not clear as to what the verb "Arimasu" means although it seems to be similar to "Desu". For example:
(Excuse me, for I do not have the tools to write in hiragana. Ill try my best in romanji.)
Tamago ga itsu arimasu
I assume this sentence means "There is an egg/There is one egg" but why wouldn't it just say "Tamago ga itsu desu". Like i said I am pretty new to this so excuse me if i am wrong. Also, i have just finished learning all my hiragana, could someone perhaps refer a website to learn katakana? In addition, I have read through the forums and i have noticed what i believe are Chinese characters. I have read that the Japanese borrowed Chinese characters in order to make the current syllabary, and they seem quite essential to understand. Could someone refer me to a place i can learn the meaning of these characters (I believe is kanji)? Again, my apologies for all these questions. Thank you for anyone taking the time to read this and help.

 

[Andromedashun]

De''ru''(Demasu, Dekakemasu...etc) can have many meanings. Desu refers to is/are is not a verb.
Arimasu means to exist.
Desu (in your case) don't have much meaning for a whole sentence since sometime desu can be omitted, arimasu only use with non-living things and sometime can be omitted as well.
Those 2 can't be described in English. They are just there to sound more convenient I think.
In your example, it should be ''hitotsu'' instead of itsu.
If you want to use desu in this case, particle wa is used instead of ga and it should be:
Tamago wa hitotsu desu.
Hope it helps.

 

[Toritoribe]

"Desu" is a copula. Wikipedia has a brief explanation of it.

Copula (linguistics) - Wikipedia, the free encyclopedia

"Tamago ga hitotsu arimasu" is a "stand-alone" description, whereas "Tamago ga hitotsu desu" can be used only in a context, for instance, as an answer to the question "What and how many items are in the box?" or like that.