"It can be considered as time of a clock that is stationery to the observer"
Rather than me typing out the argument about simultaneity perpetrated by Poincare and then fossilised by Minkowski, can I please ask that you read my post of 11/7 19.33 on my blog. This misconceived concept, along with the substitution of light speed for distance is where it all went wrong (which could have been an alternative essay)
Similarly, rather than me explaining what SR actually is, etc, Which I have done in previous posts, can you please read my post 13/7 11.24 on my blog.
"I do not know, if I am able to explain the 4th dimension or not"
On the assumption that it has some form of connection with time, then yes sufficiently for me to say that this cannot be so. Any reality (ie physically existent state) cannot involve a form of change, otherwise what is being referred to is, by definition, more than one, and the intention is to describe one, not the identified differences between 'ones'.
"However, in nature absolutes exist as constants."
Physical reality exists independently of sensory detection. Some components of it may always manifest the same value. Nothing is measured "differently". Measuring has one logical form, ie comparison to identify difference. And if one wants the various results to be comparable, then one must maintain consistency of reference.
"Speed of light is one such absolute"
The speed of light is not an absolute, neither did Einstein say it was, in the real world. Light is the result of an atomic reaction, therefore it always starts at the same speed. And by definition, if there is no impediment, it will continue at that speed (in 1905 & SR it is in vacuo, in GR it is not). Logically, calibrating the speed of light is effected the same way as calibrating the momentum of an albatross. They are both just physically existent phenomena, travelling. Of course there are certain practical difficulties, but that is another issue. In other words, the fact that subsequently, an example of light might be received by a seeing sensory system is irrelevant.
Re 3 dimensions. Careful, I do not say there are 3 dimensions, what I say is that 3 is the absolute minimum one can have and still be ontologically correct in terms of conceptualisation, ie it is the highest level possible.