How to start to trade in video technics?
Who can that advise?
What it is necessary for this purpose?
Advise how to begin.

First you need to find a supplier. There are websites like www.alibaba.com or www.made-in-china.com, but it is not a good idea to rely on online platforms to find your suppliers, many suppliers (also certified suppliers) are fake and you probably wont get your money back if you pay something in advance (and even reliable suppliers ask for payment in advance).

You can also contact a company specialized in sourcing for China which will help you finding suppliers, visiting the company, setting up a contract, finding a company with export license to take care of the shipment, quality control.
You also have to do research of the law of your own country: custom requirements, tax, import regulations, patents, license issues.

And of course you need to know how to sell the product: B2C, B2B (maybe you can find a wholesale trader in your country but this is difficult because margins in trade with China are often very small, you often find products you want to import for the same price you pay at platforms like ebay.com)..

If you don't have any experience with trade in China I recommend contacting a company specialized in sourcing. Costs for importing goods from China can be more expensive than you exspect. We have a long discussion about trading in the German version of the forum at http://forum.chinaseite.de/forum43.html. Maybe you can use a online translatioin tool (German - English) to get some information.

I recommend contacting a company specialized in sourcing. Costs for importing goods from China can be more expensive than you exspect.

This tutorial should be put in a place of honor. The best!!!

I would just add to make sure you have a good education first. It is not easy without a degree and your pay will be much better. Do it for the long run, at least.