The phrase 'firstly explain' is correct and usable in written English.
You can use it when you wish to begin a sentence by outlining the explanation you plan to provide. For example: "Firstly, explain why it is important to take regular breaks when working at a computer."
In the remaining part of this section, we firstly explain the steps performed off-line, followed by the description of the dynamic stage.
In order to define kernel functions for human motions having various time lengths, we firstly explain the LCSS kernel for human motions that uses an LCSS-based similarity in [14].
In order to explain this situation, we have to delve deeper into this analysis and to firstly explain the use of degrees of freedom, as it is important for the t-statistic.
In this section, we firstly explain a grid partition approach for real-time computation of facility influence and then we address two issues of this approach: ambiguous grid and grid size.
With regard to the proposed tests of equivalence, the authors need to firstly explain how they believe interactions should be incorporated conceptually and then demonstrate that this can actually be achieved in practice.
The authors start with ghosts, firstly explaining that the "cold chills" often experienced in haunted houses are actually just a result of poor insulation (no EU building regs in the olden days), and secondly noting the rather amusing paradox that ghosts are often portrayed as walking, despite having no physical body.
The idea behind the new detector is firstly explained, and then, its steps are designed.
The chapter firstly explains the application of the DSM for the design of simply supported and continuous purlins.
The paper firstly explains the underlying mechanisms of KBE, and the significant benefits that can be achieved from their application.
Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling are firstly explained and their applications toward understanding behavior of CNTs are discussed.
It firstly explains the fundamental governing equations and their numerical calculations via the SCM in a self-contained way, and then demonstrates the technique on the well-studied ZnO/diamond/Si material system, where the key factors of phase velocity, electromechanical coupling coefficient and effective permittivity are evaluated and discussed in detail.
