Clear[f]
f[t_] := 
      1 /; -1 ≤ t ≤ 1
f[t_] := 0
Plot[f[t], {t, -3, 3}, 
      PlotStyle -> {RGBColor[0, 0.4, 0.6], Thickness[0.008]}, 
      AspectRatio -> Automatic, 
      AxesLabel -> {"t", "f(t)"},  
      ImageSize ->  {300, 120}, 
      PlotRange -> {{-3, 3}, {-0.5, 
            1.5}}]
Table[
      Plot[f[t - u], {u, -10, 10}], {t, -10, 
        10}]
Table[
      Plot[f[t + u], {u, -10, 10}], {t, -10, 
        10}]