Estimating equation using residuals

[vad1234]

Sorry for the very basic question but I am completely new to eviews and some basic guidance/help would be very much appreciated.

Using a wrokfile with panel data on eviews 7.2, I want to estimate:

log(HP)=a + B1 log(pop) +B2 X + e

where X is 4 measurable charactersitics consisting of variables a,b,c and d.

What are the steps that need to be taken to generate the variable X so the basic regression model above could be constructed?

Help would be much appreciated