You have several questions there, let's first focus on the main question: why is there no working fusion reactor on earth as we already have the hydrogen bomb?
This is an interesting question, as a lot of people had similar expectations when the first hydrogen bomb, Ivy Mike, was ignited in 1952. They probably had the first fission bomb, Trinity, ignited in 1945 and the first (proof-of-principle) fission reactor in their minds which went critical even a few years in advance.
Directly after World War II, fusion research was conducted in secret laboratories (UK, USA, Soviet Union). It was, however, soon realized that harnessing the energy released in a fusion reaction is a bit more complicated than initially expected and in 1955 the national laboratories involved in fusion research met for the first time at an international conference (1st UN Conference on Peaceful Use of Atomic Energy). They saw that everybody had similar problems and therefore in 1958, it was decided to declassify fusion research which was quite remarkable - keep the cold war in mind.
Now, what are the main differences of a reactor to a fusion bomb? In principle, anna v has answered everything. In a bomb, you do not really care about efficiency, you just want a huge amount of energy released instantaneously. In a reactor, however, efficiency is quite important. Let's have a brief look at the fusion process.
In order to fuse two light nuclei, they need to come very close together to overcome the electrostatic repulsive force. Only if their distance is on the order of their radius, the strong force starts to act and a new nucleus is formed. If you successfully fuse two light nuclei, the resulting nucleus has a smaller mass than the sum of the two original nuclei - the difference is released as energy according to $E=mc^2$.
To bring them close together, the particles need a very high speed. Higher particle speed means higher temperature and to give some numbers, for the currently envisaged fusion reaction, deutrium + tritium, temperatures on the order of 150 Mio °C are required. At such high temperatures, matter is ionized and consist mostly of charged particles and is referred to as a plasma. Achieving these temperature is not a problem. To understand what are the problems, let's look at the fusion reaction a bit more in detail.
Deutrium + Tritium $\rightarrow$ Helium + neutron + energy
In a reactor, the released energy serves two purposes: produce electricity and keep the fusion reaction running. In the fusion reactor concept which seems to be the most promising at the moment, magnetic confinement fusion, we use a magnetic field to confine the plasma in a toroidal shape. Since the neutron is not affected by the magnetic cage, it just leaves the plasma and hits the wall (thus heating the wall and the heat can then be used to produce electricity). The Helium-nuclei, however, is influenced in its motion by the magnetic field and we need it to heat more Deuterium and Tritium to temperatures high enough to perform more fusion reactions. This requires a good confinement and as it turns out it is not so easy to keep particles at such high temperatures long enough in the magnetic cage. The key parameter here is the confinement time which has been constantly increase since the 1950 but is still slightly too small to achieve break even.
Break even is defined here as the point where the released power (in the fusion reactions) is larger than the external heating power. The record was achieved at JET, currently the largest tokamak in the world, the achieved value was $0.6$. The goal of ITER is to release for the first time more power than the initial heating power.
So the main difference in the reactor is that we need a sustained reaction process where the energy of the reaction products need to be transferred to the plasma and this can only be achieved if we have a large enough confinement time.
As for the other questions, I would suggest to ask them in separate questions.
Update 1: The Q value, which is ratio of the released power to the externally applied heating power, is planned to reach 10 in ITER in the last stage of operation. A running power plant will probably have a slightly higher value, something around 30. I will dig through my references-folder when I'm back home and see if I find something more precise there.