Hey @Josef,
It is an interesting challenge to be able to sum up the simplicity of the method. The fact is that there are actually no set conditions (no tick-list of any kind) which you need to carry out in order to feel good now, or to get back to feeling good now if you have ceased doing so.
You might be able to appreciate that there are no conditions for ‘getting to’ feel bad, ‘we’ are very good at demonstrating this one 
For a gloomy and doomy individual it is as easy as pie to manage to feel bad, the opportunities for this choice lay all around. They do not require any process or system or a step by step, they manage quite well themselves haha!
Sure they have a sophisticated worldview that justifies this feeling bad as somehow righteous or unavoidable. But the fact is that they are simply choosing to spend this moment of being alive feeling bad, each moment again.
So if you can appreciate just how easy it is to choose to feel bad, then you can consider that it is no different with feeling good, as these are felicitous and innocuous feelings, they are part of ‘my’ affective repertoire.
And what a freedom this is to discover! That truly there was nothing ever stopping you from simply feeling good now, and as such there was no conditions that you were ever restricted by in the first place.