How to make sense of principal component analysis (PCA) in MATLAB

Question

I have a data set of 3 different variables, each variable has 37 data points as follows:

Variable_1 = [0.489274770173646 0.534659090909091   0.496806966618287   0.593160935871933   0.542091836734694   0.514607775477341   0.580715497052410   0.542977656178750   0.624465240641712   0.644904791797447   0.444644611857190   0.464080100125156   0.522286821705426   0.507719139590466   0.612791008830612   0.561735261401557   0.524166666666667   0.526627218934911   0.449009900990099   0.472768878718535   0.488477561567263   0.576187425642902   0.558307692307692   0.609308792372882   0.647109905020352   0.513392857142857   0.454701120797011   0.557692307692308   0.511568509615385   0.440248676030394   0.500000000000000   0.593340146482712   0.518269230769230   0.623676307886835   0.563086974275214   0.609080188679245   0.769444444444444] 
Variable_2 = [0.573717948717949 0.489656381486676   0.443821689259645   0.578812453392990   0.678328092243187   0.476432291666667   0.460748792270531   0.593650793650794   0.585645494152717   0.540435139573071   0.536423112870416   0.471528337362342   0.514469014469015   0.459801313718039   0.674409015942826   0.526881720430108   0.437327188940092   0.531890398342160   0.479985035540591   0.449145299145299   0.553381642512077   0.524932614555257   0.652630308880308   0.561587521131090   0.560003234675724   0.537254901960784   0.521990521327014   0.466041489059392   0.571461291800275   0.413770728190339   0.493939393939394   0.458024968229051   0.579528535980149   0.512145748987855   0.567205861018424   0.463562753036437   0.562938596491228] 
Variable_3 = [0.630327868852459 0.521367521367521   0.467658730158730   0.485012755102041   0.523217247097844   0.449032738095238   0.574519230769231   0.594594594594595   0.544390243902439   0.581524147097918   0.487662337662338   0.497564726993079   0.417307692307692   0.609668109668110   0.508928571428572   0.511870845204179   0.444067796610169   0.562337662337663   0.494043887147335   0.530476190476191   0.484235294117647   0.502136752136752   0.632418524871355   0.528787878787879   0.619780219780220   0.416958041958042   0.552419354838710   0.586057692307692   0.461351186853317   0.495276653171390   0.524305555555555   0.655671296296296   0.496873496873497   0.462542087542088   0.660491689750693   0.772549019607843   0.558589870903674]

I put all three variables in a matrix, where the columns are the variables and the rows are the 37 data points.

I uses the PCA function in MATLAB and it gives me the following matrix:

PCA = 0.6370    0.3070    0.7071
      0.3494    0.7026   -0.6199
      0.6871   -0.6420   -0.3403

First Question: What does each row and each column represent in the PCA matrix.

Second Question: How can I use this matrix to plot each variable along its principle component in 3 dimensions.

Thank you, I very appreciate any help