about non linier regression

I have a formula to get Nonlinear regression. But I have a problem to define tbl and b. May be is there anybody can help me to solve my problem.

Thx.

tbl = table(Amax,Mw,Vs, Depth, Distance); modelfun = (@(b,RegAll)b(1) + b(2)*RegAll(:,1)+b(3)*RegAll(:,2)+b(4)*RegAll(:,3))/(b(5)+b(6)*exp.^(b(7)*RegAll(:,4)+b(8)*RegAll(:,5))); beta0 = [-3 0.9 0.05 0.3 0.1]; mdl = fitnlm(tbl,modelfun,beta0);