How to resample a data file using specific indices? And not using the resample function

The resampling index goes from [1:2:70000]. How do I incorporate this into data file (70000x1) to resample it?

Because of this problem I'm having difficulty creating a function to resample any general data that lets the user change the factor of steps in which the signal is resampled (in this case 2) with resampled signal and resampled Sr as output. Any leads on that also?

So far I have something messy... And it also includes the resample function which I need to change

% manufactures steps for resampling a clip
function [newclip, Sr] = generateresample (levels, Nsteps, Nsamples, originalsteps, originalSr, timeformeasurement)
levels = [1:Nsteps:Nsamples]; 
resampleclip = resample(data,1,Nsteps);
timeformeasurement = originalsteps/originalSr;
Sr = Nsteps/timeformeasurement;
end
end

But I think this needs too much input and I also don't know how to link it all together under the function