This article explains some of the basic metrics that you can see when you are mining with the Idle-Empire miner.
The hashrate is the amount of hashes (calculations) that your computer solves per second. It is sometimes also displayed as H/s which means hashes per second. This metric is probably the most important of for you as it determines how much you earn - a higher hashrate means that you receive more points because we pay for every hash that your computer solves.
Accepted hashes are the hashes that have been verified by the server. Not every single hash that your computer solves can be verified by the server, this is why estimations are being used.
Imagine you have a hashrate of 500 H/s and you run the miner for 100 seconds. 500 hashes per second multiplied by 100 seconds equals 50,000 hashes. Your computer solved 50,000 hashes but it might happen that only 40,000 hashes are accepted by the server, or that 60,000 hashes are accepted by the server.
The server uses an estimation technique which requires you to find a hash that has a certain difficulty, e.g a hash that only has a probability of 1/5000 to be found. On average your computer will find such a hash only every 5,000 hashes and when he finds it, he sends the hash to the server. And because of the mathematical probability, the server can estimate that your computer needed to solve 5,000 hashes in order to find this one hash. But in reality, your computer needed 4,000 or maybe 6,000 calculations until he found the hash.
This is how accepted hashes are different than the hashes that your computer solves in reality. But due to the mathematical probability, the number of accepted hashes is very close to the number of hashes that your computer really solved over time.
A thread is a process in your operating system which is performing the hash calculations. Depending on your hardware, you can have multiple threads which run simultaneously.
Note: This does NOT mean that you should open the Idle-Empire miner multiple times! This will decrease your hashrate because it is too much for your computer. One instance of the mining client can run multiple threads in the background.