How can I use system identification toolbox to process and analyze data model in the form of output values versus time with one step input value?

Dear, colleagues, I have a problem in the model or the data that system identification toolbox can process and analyze. The only data model I have is time domain signal in terms of (t) time vector and (y) pressure vector all as a response of step input, I have coordinates/ points which mean at specific time what could be the value of the pressure (t0, y0), (t1, y1), (t2, y2),… when step input is applied, the signal in this form is showing the transient and steady response when one step input is applied. However system identification toolbox requires measured data in terms of values of inputs (u) and outputs (y) as steady states values such as (u1,y1),(y2,y2),(u3,y3)… which means several inputs with corresponding steady states outputs. I tried to feed the system with the (t) vector that I have as inputs data and (y) as output data, but the outcome I obtained seemed as expected to be not correct. Since I have only signal in terms of (t) time vector and (y) pressure vector as a response of one step input, do you have an idea how can the system identification toolbox accept do deal with my coordinates model? At the end to I need to estimate the transfer function of the pressure signal in Laplace form in order to conduct further control analysis on the pressure system.