Hi Robert, let's go through your list.
Robert B. wrote:I want to record sounds (i like high quality sounds - im very sensitive to it) - but can't afford mixing engineer to sort out gear issues (so i have to search for my own)
Which makes you prone to trying to get "the best" instead of getting "what's needed".
I want to buy RME Fireface UFX interface and RME Micstasy as a mic preamp so i have a questions about this:
Why do you want to buy this combinations? How many inputs do you need?
1. I understand UFX have its own A-D convernters so the Micstasy - wich one to use ? wich one have superior conventers and if i use converters on Micstasy - what cable should i buy to transmit digital signal to UFX? (watched some videos but they are targeted to medium or advanced users)
The differences are more about function and internal build, not necessarily converters. They are different tools for different applications that partly overlap each others use.
You can connect the 8 Micstacy input via ADAT out to the UFX via optical ADAT cable, but since the Micstacy lacks ADAT in you cannot go the other way around. You can connect 2 inputs and outputs via AES cabling. But overall the UFX is not the interface to connect the Micstacy to, you rather need a MADI or AES interface for that.
2. If you have a good A-D converter and good mic preamp whats the point of owning good interface?
The Micstasy is not a computer interface, it's a preamp + converter. So you need some kind of connection between Micstasy and computer. There are many uses for the Micstacy where a computer connected isn't needed, like recording an orchestra in the hall and then transmitting the audio digitally over hundreds of meters to a control room mixer and recorder.
Seriously and nicely, despite the bold font: If you do not know about phantom power then pretty please do *NOT* spend thousands of Euro on equipment. It is way beyond your current level of expertise. Just get the UFX, UCX or Babyface based on the number of inputs/outputs (I/O) you need, get a (pair of) semi-pro microphone(s) - preferably suggested by some local audio dealer or just the Thomann hotline - and be good for a clear start!
Condenser mics need 48v phantom power to work, "dynamic" mics don't. This power is provided by the pre-amp of a mixer, interface or Micstacy like preamps. That being said, the Schoeps come with their own pre-amp built-in, so you likely wouldn't use the pre-amps of the Micstacy anyway. There also seems to be a digital version of the Schoeps, which should be able to digitally connected directly to a RME interface (UFX/UFC/BF), but I couldn't find info about that. Just ask your local dealer or Thomann.
4. Whats a STEADY CLOCK? and what Clock does in this gear?
When several interfaces are connected then one has to be the Master clock (there are also dedicated stand-alone Master clocks available), the others are "slaved" to that Master. Clocks can produce jitter (irregularities) which Steady Clock corrects for when it's connected to a jittery clock. So a RME interface that is slaved to a jittery clock will first correct the jitter as good as possible and then run its internal parts synced to the "corrected" clock signal. This improves signal quality.
Any link to articles instead of explaining everything first hand will do.
There is no one link, because you are hitting several walls of not knowing basic and advanced audio stuff. People learn these things for a living, so it's not like you can get it all from one page. 
There are books out there, lots of web-pages (Wikipedia can help) and the RME Tech Info, FAQ and Glossary pages found here:
http://www.rme-audio.de/en/support.php
Again, don't go for expensive equipment that you deem "best", get something decent enough to get going and rather spend the money on education and a living.
