and how do i post a trade

If you're just trying to mine with with your pc use nicehash, all you have to do is download and install and then click start and tick the box that says to mine after benchmarking.

ok thx

Are there any risks I have to look out for while mining with nicehash?

if you manage to get ur temp below 75 c (better below 70) while mining . there is no risks its like gaming .

i have 6 x AMD RX 580 mining rig working since 14 months perfectly

I know im late but.... mining with your pc will or being be slow depends on the cpu

do not get into mining, rather, learn about the technology (I recommend andreas antonopoulos' youtube channel, he is excellent at explaining what a revolutionary technology this is and why it matters). The open, decentralized internet is coming for banking and many other applications/use-cases in much the same way that the internet came for the printing press / mainstream media television... it WILL consume/transform those industries and the way we communicate value to each other.

Once you have learned about it perhaps pick up small amounts of promising alt coins and a little bitcoin if you have funds. But never invest more than you can afford to lose; this is extremely early in the crypto space and no one can predict what will happen. One thing I think for sure though, is that some decentralized, open, trustless networks will thrive, and the wider industry/banks will move to try and protect themselves with permissioned closed cryptos (these are not true cryptos and in my opinion will be an extention of the current dystopian nightmare surveilance control network that the banks currently operate)

Otherwise, look at airdrops/giveaways and accumulate those for free, in time they may be worth something and you may be able to make a little bitcoin out of those without investing. IMHO bitcoin will probably survive and thrive, scalability and privacy enhancement innovations are coming thick and fast, but scaling is something that will happen over the next decade or two as the networks current capacity is used... this scaling is exponential in nature much like the how the internets infrastructure scaled, rather than linear, how visa/banks scale (barely/slowly and in a way that excludes the majority of the worlds population).

(for anyone new to bitcoin/crypto, you will be doing yourself a massive favour by checking those two incredible resources)

andreas antonopoulos youtube channel
https://www.youtube.com/user/aantonop

check his full talks in chronological order, and q&a specific videos about topics you find interesting from there

Jameson Lopps massive trove of various bitcoin resource links:
https://lopp.net/bitcoin.html

Mining is a really complicated process imo. But there are many tutortials on YouTube